Intermediate transfer ink jet recording method

ABSTRACT

Two intermediate transfer ink jet recording methods and a recording device suitable for practicing the methods and an ink composition for use in the methods are disclosed. The first recording method comprises forming jetting an ink composition containing a thermoplastic resin on an intermediate transfer drum to form an ink image, heating the ink image to at least the softening or melting temperature of the thermoplastic resin to bring the ink image to a film form and then transferring the ink image to recording paper. The second recording method comprises jetting an ink composition containing a thermoplastic resin on an intermediate transfer drum to form an ink image, heating the ink image to form a concentrated ink image, transferring the concentrated ink image to recording paper and then heating the transferred ink image to at least the softening or melting temperature of the thermoplastic resin. According to the recording methods of the present invention, a good print can be provided independently of the quality of the recording paper and even under a low transfer pressure.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ink composition for use in anintermediate transfer ink jet recording device and an intermediatetransfer ink jet recording method and an intermediate transfer ink jetrecording device using the ink composition.

2. Background Art

An ink jet recording system is advantageously excellent in thesimplicity of the mechanism and noiseless. This type of printing,however, has problems including that the quality of prints variesdepending upon recording media (for example, depending upon propertiesof recording paper) and also including that the image of a portionremaining undried of an ink image is disturbed when the recording mediumis discharged. In order to cope with such problems, a proposal has beenmade on a method called an "intermediate transfer system" wherein an inkimage is once formed on a transfer medium by an ink jet recordingprocess and then transferred to a recording medium (Japanese PatentLaid-Open No. 225958/1984 and U.S. Pat. No. 4,538,156). In this method,a recording head can be disposed apart from the recording paper.Consequently, this method successfully prevents the recording head fromclogging which is due to the possibility that the recording headcontacts with the recording paper since they are disposed closely orthat paper lint from the recording paper is attached to the recordinghead. However, in the intermediate transfer ink jet recording method,there is room for an improvement in the quality of the image transferredon the recording medium.

Furthermore, Japanese Patent Laid-Open Nos. 2849/1987, 169643/1991 and284948/1991 and U.S. Pat. No. 5,099,256 propose a method which comprisesthe steps of ejecting ink droplets on a transfer medium to form an inkimage, evaporating a large proportion of water in the ink image todehydrate the ink image to a substantially dry state and transferringthe concentrated ink to recording paper. In this transfer ink jetrecording method, however, high pressure is necessary for transferringthe ink image to the recording medium, since the bonding force betweenthe recording medium and the ink image is small. The provision of meansfor applying necessary pressure renders the recording devicecomplicated.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide an inkcomposition for intermediate transfer ink jet recording that enables anexcellent quality and a good fixing strength of prints to be attainedindependently of a recording medium used.

Another object of the present invention is to provide an ink compositionfor intermediate transfer ink jet recording that is free from theclogging of the ink jet recording head and can simplify the transfer andfixing operation.

A further object of the present invention is to provide an intermediatetransfer ink jet recording method using the above ink composition forink jet recording, which method enables an excellent quality and a goodfixing strength of prints to be attained independently of a recordingmedium used.

A further object of the present invention is to provide an intermediatetransfer ink jet recording method that enables a good ink image to betransferred from an intermediate transfer medium to a recording mediumunder low pressure.

A further object of the present invention is to provide an intermediatetransfer ink jet recording device suitable for an ink jet recordingmethod using the above ink composition.

The intermediate transfer ink jet recording method according to thefirst aspect of the present invention comprises the steps of:

ejecting an ink composition comprising water, a thermoplastic resin, acolorant and a water-soluble organic solvent on an intermediate transfermedium to form an ink image;

heating the ink image to at least the softening or melting temperatureof the thermoplastic resin; and

transferring the ink image in the heated state on the transfer medium toa recording medium.

The intermediate transfer ink jet recording method according to thesecond aspect of the present invention comprises the steps of:

ejecting an ink composition comprising water, a thermoplastic resin, acolorant and a water-soluble organic solvent and, when the thermoplasticresin is a water-insoluble resin, further comprising a water-solublepolymer on an intermediate transfer medium to form an ink image;

concentrating the ink image;

transferring the ink image in the heated state on the transfer medium toa recording medium; and

heating the ink image on the recording medium to at least the softeningor melting temperature of the thermoplastic resin.

The ink composition for use in the intermediate transfer ink jetrecording method according to the first aspect of the present inventioncomprises water, a thermoplastic resin, a colorant and a water-solubleorganic solvent.

The ink composition for use in the intermediate transfer ink jetrecording method according to the second aspect of the present inventioncomprises water, a thermoplastic resin, a colorant and a water-solubleorganic solvent and, when the thermoplastic resin is a water-insolubleresin, further comprises a water-soluble polymer.

The first intermediate transfer ink jet recording device according tothe present invention comprises:

an intermediate transfer medium;

recording means for ejecting droplets of an ink composition comprisingwater, a thermoplastic resin, a colorant and a water-soluble organicsolvent to form an ink image on the intermediate transfer medium;

heating means for heating the ink image on the intermediate transfermedium to at least the softening or melting temperature of thethermoplastic resin; and

transfer means for pressing the ink image formed on the intermediatetransfer medium against a recording medium to transfer the ink image tothe recording medium.

The second intermediate transfer ink jet recording device according tothe present invention comprises:

an intermediate transfer medium;

recording means for ejecting droplets of an ink composition comprisingwater, a thermoplastic resin, a colorant and a water-soluble organicsolvent and, when the thermoplastic resin is a water-insoluble resin,further comprising a water-soluble polymer to form an ink image on saidintermediate transfer medium;

first heating means for concentrating the ink image formed on theintermediate transfer medium;

transfer means for pressing the ink image formed on the intermediatetransfer medium against a recording medium to transfer the ink image tothe recording medium; and

second heating means for heating the ink image on the recording mediumto at least the softening or melting temperature of the thermoplasticresin.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an ink jet recording device for the inkjet recording method according to the first aspect of the presentinvention;

FIG. 2 is a cross-sectional view in the direction of X of the deviceshown in FIG. 1;

FIG. 3(a) is a schematic view of a form of an ink image immediatelyafter formed on the transfer drum of the recording device according tothe present invention;

FIG. 3(b) is a schematic view of the form of an ink image brought to afilm form on the transfer drum of the recording device according to thepresent invention, together with a "peeling layer" formed between theink image and the transfer drum;

FIG. 4 is a schematic diagram showing the transfer of an ink image tothe recording medium in the recording device according to the presentinvention;

FIG. 5 is a perspective view of an ink jet recording device for the inkjet recording method according to the second aspect of the presentinvention;

FIG. 6 is a cross-sectional view in the direction of X of the deviceshown in FIG. 5;

FIG. 7 is a diagram showing an ink jet recording device according to thepresent invention, wherein an image is intermittently formed as astriped region on a transfer drum;

FIG. 8 is a diagram showing an ink jet recording device according to thepresent invention, wherein an image is formed in a spiral form on atransfer drum;

FIG. 9 is a diagram showing an ink jet recording device according to thepresent invention, which has a recording head having nozzles providedover the whole printing region;

FIG. 10 is a diagram showing an ink jet recording device according tothe present invention, which has a heater provided outside a transferdrum;

FIG. 11 is a diagram showing an ink jet recording device according tothe present invention, which has a heater and a transfer drum integrallyconstructed;

FIG. 12 is a diagram showing an ink jet recording device according tothe present invention, which has a heater and a pressure rollerintegrally constructed;

FIG. 13 is a diagram showing an ink jet recording device according tothe present invention, wherein cooling means for cooling a recordingmedium having a transferred image is further provided on the deviceshown in FIG. 12;

FIG. 14 is a partially perspective view of the device shown in FIG. 13;and

FIG. 15 is a schematic view of a preferred embodiment of the secondheating means in the recording method according to the second aspect ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

Recording Method and Device

According to the present invention, there are provided two recordingmethods and two devices for the methods. In the ink jet recording methodaccording to the first aspect of the present invention, an inkcomposition comprising water, a colorant, a thermoplastic resin and awater-soluble organic solvent is employed (This method is hereinafteroften referred to as "recording method A". The device used forpracticing this method is hereinafter referred to as "recording deviceA"). In the ink jet recording method according to the second aspect ofthe present invention, an ink composition comprising water, a colorant,a thermoplastic resin and a water-soluble organic solvent and, when thethermoplastic resin is a water-insoluble resin, further comprising awater-soluble polymer is employed (This method being hereinafter oftenreferred to as "recording method B". The device used for practicing thismethod is hereinafter referred to as "recording device B").

The recording method A and the recording device A according to thepresent invention will now be described with reference to theaccompanying drawings.

FIG. 1 is a perspective view of a device for the recording method Aaccording to the present invention. FIG. 2 is a cross-sectional view inthe direction of X of the device shown in FIG. 1. This device comprisesa transfer drum 1 as an intermediate transfer medium and ink jetrecording means 2 and a pressure roller 3 which are disposed around thetransfer drum 1 from the upstream side in the direction of rotation ofthe transfer drum 1.

The transfer drum 1 comprises an elastic layer 11 constituting thesurface of the drum 1 and an internal drum 12. A recording medium 4 issandwiched and supported between the transfer drum 1 and the pressureroller 3, and carried with the rotation of the recording drum 1 and thepressure roller 3. The transfer drum 1 is heated by a heater 5 which isheating means provided inside the transfer drum 1. The heater 5 heatsthe surface of the transfer drum 1 to at least the softening or meltingtemperature of the thermoplastic resin contained in the ink so that theink image can be transferred in the following manner. (The transfer inthe following manner is hereinafter often referred to as "interfacialtransfer". The ink image ready for the interfacial transfer ishereinafter often referred to as an ink image "brought to a film form".)The pressure roller 3 can press the recording medium 6 against thetransfer drum 1 by taking advantage of the pressure applied bypressurizing means 30. If necessary, the pressing of the pressure roller3 against the recording medium 6 can be released by pressure releasemeans 31. Furthermore, if necessary, cleaning means 7 for removing aremaining ink or the like after the transfer of the-ink image may beprovided downstream of the pressure roller 3.

In this device, printing is effected as follows. Firstly, recordingmeans 2 (an ink jet recording head) ejects droplets of the inkcomposition onto the transfer drum 1 to form an ink image 8. The inkimage 8 immediately after it is formed can take a form as shown in FIG.3(a). The ink image 8 is heated on the transfer drum 1 by the heater 5.The heating causes the solvent to be evaporated from the ink image 8.This increases the solid component concentration. Finally, anagglomerate consisting essentially of solid components is formed on thetransfer drum 1. Furthermore, since the agglomerate is heated on thetransfer drum 1 to at least the softening or melting temperature of thethermoplastic resin contained in the ink, particles constituting theagglomerate of solid components are softened or melted. As a result,they are mutually dissolved and homogenized to bring the ink image to anink image 8a in a film form having a substantially homogeneous thicknessas shown in FIG. 3(b). The surface of the ink image 8a is viscous in theheated state.

More interestingly, in the ink composition of the present invention, alayer 9 of a water-soluble organic solvent (hereinafter often referredto as a "peeling layer") is formed between the ink image 8a and thetransfer drum 1 with forming the ink image 8a. (An expected mechanismthrough which the peeling layer is formed will be described later.) Asis apparent from the following description, the formation of the layer 9is advantageous for the interfacial transfer.

Subsequently, the ink image 8a in the heated state is carried to aregion facing the pressure roller 3 with the rotation of the transferdrum 1 and then transferred to the recording medium 4. This will now bedescribed in more detail with reference to FIG. 4. In this device, thetransfer drum 1 is pressed through the recording medium 4 against thepressure roller 3. In the recording method according to the presentinvention, three forces, that is, an adhesive force (F1) between the inkimage 8a and the recording medium 4, a cohesive force (F2) of the inkimage 8a and an adhesive force (F3) between the ink image 8a and thesurface of the transfer roller 1 have the relationship F1>F2>F3.Therefore, one interface of the ink image 8a is wholly peeled off fromthe surface of the transfer drum 1 whereas the other interface of theink image is wholly adhered to the recording medium 4. Especially, thepresence of the layer 9 of the organic solvent is advantageous becausethe F3 value becomes smaller. Thus, the ink image 8a is peeled andadhered at its interface, so that the untransferred remaining image canbe effectively prevented. Furthermore, in the present invention, it ispossible to realize a large F1 force, which enables transfer to besuccessfully effected even when the pressure applied by the pressureroller 3 is low.

According to a preferred embodiment of the present invention, the inkcomposition may further comprises a saccharide. The saccharide serves tobind the solid component in the ink image to increase the cohesive forceF2 and, at the same time, to increase the adhesive force F1 when the inkimage has been brought to a film form. As a result, stable cohesiveforce F2 which stabilizes the ink image can be obtained independently ofthe printing pattern, so that not only good transfer and printing can beeffected but also the ink image can be transferred from the transferdrum to the transfer medium under low pressure. In addition, thesaccharide serves to stably impart the increased adhesive force to theink image for a long period of time. Therefore, the time taken from theformation of the ink image to the transfer of the ink image can beadvantageously set at will.

A further great advantage of the present invention is that a thicknessof about 2 to 10 μm suffices as the thickness of the ink image broughtto a film form on the transfer drum for finally obtaining a sufficientimage density (for example, 1.4 or more of the OD value) on therecording medium 4. Specifically, in the case of the conventionalintermediate transfer ink jet recording method, the pressure applied inthe transfer of the ink image to the recording medium is so high thatthe ink image is unfavorably deformed (that is, defaced), which causesthe deterioration in the quality of the image. By contrast, in thepresent invention, the thickness of the ink image on the transfer drum 1is about 2 to 10 μm, that is, sufficiently smaller than 120 μm which isthe diameter of one dot as the minimum pixel in 300 dpi recording.Therefore, the present invention is advantageous also in that thedeformation of the ink image is so small that no defacing of the imageis observed in the transfer of the image to the recording medium.

In the recording method according to the present invention, goodtransfer can be effected independently of the kind of the recordingmedium, more specifically, independently of the surface profile of therecording paper. The ink image 8a can be transferred in "one" onto therecording medium 4 since the ink image 8a brought to a film form has acertain cohesive force F2. Even though the recording medium issignificantly uneven (for example, bond paper), the ink image 8a can betransferred with maintaining its shape because the ink image 8a can beadhered to the recording medium with an adhesive force attained merelyby the contact of the ink image 8a with protrusions of the recordingmedium. Therefore, good transfer can be provided as no deficiency of theimage attributable to the uneven surface of the recording medium occurs.

Thereafter, the ink image 8a transferred to the recording medium 4 isnot heated any more and then solidified. Even after the solidification,the adhesive force F1 of the ink image 8a remains still large, so that agood fixation of the ink image can be provided.

The term "ink image" used herein is intended to mean both an imageconsisting of one dot as the minimum pixel alone and an image comprisinga gathering of a plurality of dots adjacent and connected to each other.

The recording method B and the recording device B for the recordingmethod B according to the present invention will now be described withreference to the accompanying drawings.

FIG. 5 is a schematic cross-sectional view of a device for the recordingmethod B according to the present invention. FIG. 6 is a cross-sectionalview in the direction of X of the device shown in FIG. 5. The some partsof this device is the same as that of the device shown in FIG. 1. InFIGS. 5 and 6, the parts common to FIGS. 5 and 6 and FIG. 1 areindicated with the same reference numerals. The difference of thedevices shown in FIGS. 5 and 6 from the device shown in FIG. 1 is,firstly, that a heat 5 "concentrates" the ink image formed on thetransfer drum 1 in such a manner that the ink image can be transferredby the interfacial transfer. In addition, this device is furtherprovided with heating means 9. In this embodiment, the heating means 9comprises a roller 9b internally having a heating element 9a and aroller 9c facing the roller 9a with a recording medium between therollers 9b and 9c. The heating means 9 is constructed so that thesurface of the recording medium is heated to at least the softening ormelting temperature of the thermoplastic resin contained in the ink.

Printing is performed as follows. Firstly, recording means 2 ejectsdroplets of the ink composition onto the transfer drum 1 to form an inkimage 8 on the transfer drum. The ink image 8 can take a form as shownin FIG. 3(a) as the recording method A. The formed ink image 8 is heatedon the transfer drum 1 by the heating means 5. The heating causes thesolvent to be evaporated from the ink image 8. In this case, the heatingis effected in such a manner that the thermoplastic resin contained inthe ink composition is neither softened nor melted. Specifically, theheating in this recording method and the heating in the recording methodA are common to evaporation of most water in the ink image to enhancethe solid component concentration. However, this recording method isdifferent from the recording method A in that the thermoplastic resincontained in the ink composition is neither softened nor melted. Theheating increases the solid component concentration. Finally, anagglomerate consisting of solid components is formed on the transferdrum 1. The agglomerate has a cohesive force considered attributable tothe water-soluble thermoplastic resin or the water-soluble polymerincorporated when the thermoplastic resin is a water-insoluble resin.This cohesive force brings the ink image to an ink image 8a in a filmform having a substantially homogeneous thickness as shown in FIG. 3(b).The surface of the ink image 8a is viscous in the heated state. As aresult, interestingly, the concentrated ink image can be transferred tothe recording medium by the interfacial transfer. (Therefore, in therecording method B, as in recording method A, the ink image in thisstate is often called an ink image "brought to a film form".) The way ofthe "concentration" is not limited to any specific embodiment so far as,as described above, it serves to increase the solid componentconcentration of the ink image while preventing the softening or meltingthe thermoplastic resin. However, it is preferred to use any one of amethod where a large amount of energy is applied in a short time toevaporate the solvent (for example, heating is effected at a temperatureof 100° C. or above in a short time) and a method where heating iseffected at a low temperature (for example, at a temperature of 100° C.or below) for a relatively long period of time to evaporate the solvent.

According to a further preferred embodiment of the present invention,the ink composition used in this method contains a water-soluble polymereven when the thermoplastic resin is a water-soluble resin. Theagglomerate, i.e., the ink image 8 brought to a film form is conveyed toa region facing the pressure roller 3 with the rotation of the transferdrum 1 and then transferred to the recording medium 4. Also in thiscase, the three forces, i.e., the adhesive force (F1) between the inkimage 8 and the recording medium 4, the cohesive force (F2) of the inkimage 8 and the adhesive force (F3) between the ink image 8 and thesurface of the transfer roller 1 have the relationship F1>F2>F3, so thatthe ink image can be transferred by the interfacial transfer.

Also in this case, when the ink composition contains an organic solvent,an organic solvent layer 9 is formed. As a result, F3 becomes smaller,which is advantageous for the interfacial transfer.

Also in the recording method B, an ink composition containing asaccharide may be employed. This enables the recording method B to enjoythe advantage as described in connection with the recording method A.

In this embodiment, the ink image transferred to the recording medium isthen heated by the heating means 9. Since the heating temperature is atleast the softening or melting temperature of the thermoplastic resincontained in the ink, particles constituting the agglomerate of solidcomponents are softened or melted and mutually dissolved in one anotherto form a homogeneous ink image in a film form. As a result,improvements in cohesive force within the ink image and also in adhesionto the recording medium can be attained, so that a good print qualitycan be realized.

Also in the recording method B, a thickness of about 2 to 10 μm sufficesas the thickness of the ink image brought to a film form on the transferdrum for finally obtaining a sufficient image density (for example, 1.4or more of the OD value) on the recording medium 4. Therefore, recordingmethod B also can enjoy the advantage that a deterioration in the imagedue to defacing of the image is hardly observed.

The device according to the present invention will now be described inmore detail.

The elastic layer 11 of the transfer drum 1 preferably comprises arubber material, particularly preferably comprises a material thatpermits an ink image to be easily peeled off therefrom and isheat-resistant. Preferred examples of the rubber material include achloroprene rubber, a nitrile rubber, an ethylene/propylene rubber, asilicone rubber, a fluorosilicone rubber, a fluororubber, a naturalrubber, a styrene rubber, an isoprene rubber, a butadiene rubber, anethylene/propylene/butadiene polymer and a nitrile/butadiene rubber. Asilicone rubber, a fluorosilicone rubber and a fluororubber arepreferred from the viewpoint of heat resistance.

As described above, the ink ejected as an ink droplet forms an ink image8 on the transfer drum 1. If the ink image 8 is repelled or flows on thetransfer drum, no desired ink image (for example, having a desired dotdiameter) can be realized. In order to prevent this unfavorablephenomenon, it is preferred to use an ink composition adjusted to have asuitable capability of wetting the surface of the transfer drum byadding a surfactant.

The image on the transfer drum 1 is formed with the ink jet recordingmeans 2. Examples of the recording means 2 include an ink jet recordinghead using a piezoelectric element.

An image on the transfer drum 1 with this recording head 2 can be formedby using various methods. The formation of the image by using thetransfer drum 1 and the recording head 2 shown in FIG. 1 will now bedescribed as an example with reference to FIG. 7. In the device shown inFIG. 7, scanning is performed in the direction of arrow Y along acarriage shaft 20 parallel to the shaft of the transfer drum 1. Whilethe recording head 2 reciprocates along the carriage shaft, the headeffects printing when it is in a printing region L except that theprinting is suspended when the recording head 2 is outside the region L.The rotation of the transfer drum 1 is suspended when the recording head2 is in the region L. On the other hand, the transfer drum 1 is rotatedin the direction of A shown in the Figure at a given angle when therecording head 2 is outside the region L. The repetition of thereciprocated scanning of the recording head 2 with the intermittentrotation of the transfer drum 1 causes a region having an image formedon the transfer drum 1 to be increased as a striped region. As shownFIG. 7, striped regions 101, 102, 103 and 104 are successively formed.

In a device shown in FIG. 8, the recording head 2 is moved at a givenrate along the carriage shaft 20 parallel to the shaft of the transferdrum 1 while rotating the transfer drum 1 at a given rate. As a result,regions 110, 111 printed on the transfer drum 1 are increased in aspiral form. In this device, the recording head 2 has two ink jetrecording heads.

In a device shown in FIG. 9, a recording head 2 all over the printingregion L is employed. In this device, the recording head 2 is fixed. Thetransfer drum 1 is rotated at a given rate, which causes a printingregion 120 to be continuously increased in the circumferential directionof the transfer drum.

Among the above image forming methods, in the device shown in FIG. 8,the transfer of the ink image onto the recording medium should beeffected after one page of an ink image is formed on the transferdrum 1. On the other hand, in the devices shown in FIGS. 7 and 9, thetransfer of the ink image onto the recording medium may be effectedafter one page of an ink image is formed on the transfer drum 1(provided that the circumferential length of the transfer drum 1 issufficient to record one page of ink image), or alternatively thetransfer may be effected in the course of the formation of one page ofthe ink image. For example, in a device shown in FIG. 7, i.e., a deviceshown in FIG. 1, the pressure roller 3 is aparted from the transfer drum1 by the pressure release means 31 (the recording medium 4 as wellremaining uncarried yet) until one page of the ink image is formed onthe transfer drum 1. After one page of the ink image is formed on thetransfer drum 1 and the ink image is brought to a film form by heating,the pressure roller 3 is pressed against the transfer drum 1 by thepressurizing means 30. At the same time, the recording medium 4 iscarried to transfer the ink image onto the recording medium 4. On theother hand, when the ink image to the recording medium is transferred inthe course of the formation of one page of the ink image on the transferdrum, the process is performed as follows. Specifically, the pressureroller 3 is previously pressed against the transfer drum 1 by thepressurizing means 30. The ink image brought to a film form by heatingis continuously transferred to the recording medium 4 before one page ofthe ink image is completely formed.

The heater 5 heats the surface of the transfer drum 1 to at least thesoftening or melting temperature of the thermoplastic resin contained inthe ink composition so that the ink image can be brought to a film form.The heating temperature may be arbitrarily determined by taking therecording conditions such as the ink image forming method intoconsideration. When the softening or melting temperature is between 50°C. and 150° C., the image is heated in such a manner that thetemperature is at least the softening or melting temperature of thethermoplastic resin and preferably in the range of from 50° to 200° C.,still preferably in the range of from 50° to 180° C.

Although specific heating means may be arbitrarily selected, preferredexamples of the heating means include a combination of a heater lampwith a reflecting mirror.

As shown in FIG. 10, the heater 5 may be provided outside the transferdrum 1 but not inside the transfer drum 1. This embodiment isadvantageous in that the ink image alone can be directly heated andreduce the heat conduction to the portion other than the ink image, forexample, recording head 2. In addition, the warm up time taken forreaching a desired temperature in the transfer drum 1 can be shortened.

As shown in FIG. 11, the transfer drum may be provided integrally withthe heating means. In this embodiment, a heater layer 14 (for example, aceramic heater) is provided on the insulating layer 13 which is providedon an internal drum 12. The elastic layer 11 is provided on the heaterlayer 14. The surface of the transfer drum is heated by the heater layer14.

According to a further preferred embodiment of the present invention,the heater 5 is constructed integrally with the pressure roller 3 asshown in FIG. 12. In this device, heating means 5 (for example, aheater) is provided inside the pressure roller 3. In this device,printing is effected as follows. The pressure roller 3 is first providedsomewhat apart from the transfer drum 1 by the pressure release means31. In this case, the transfer drum 1 is heated to a desired temperatureby the heater 5 provided inside the pressure roller 3. The ink image 8formed by the recording head 2 is heated and brought to a film form bythe heater 5. Thereafter, the pressure roller 3 is pressed against thetransfer drum 1 by the pressurizing means 30. At the same time, therecording medium 4 is carried to transfer the ink image to the recordingmedium. Alternatively, from the beginning, the pressure-roller 3 may bepressed against the transfer drum 1 to heat the transfer drum 1. In thiscase, a series of procedures comprising the formation of an ink image,the conversion of the ink image to a film form and the transfer of theink image in a film form to the recording medium may be performed in acontinuous manner. More interestingly, in the device shown in FIG. 12,it is possible to simultaneously bring the ink image to a film form andtransfer the ink image to the recording medium by properly settingconditions, such as the temperature of the heater 5 and the number ofrevolutions of the transfer drum 1. Specifically, the ink image formedby the recording head 2 is heated while pressed between the pressureroller 3 and the transfer drum 1 against the recording medium 4 to bringthe ink image to a film form and transfer the ink image to the recordingdrum.

According to a preferred embodiment of the present invention, there isprovided a recording device as shown in FIG. 13. FIG. 14 is a partiallyperspective view of the device shown in FIG. 13. The device shown inFIG. 13 comprises the elements shown in FIG. 12 and further severalelements. This device is provided with a carrier guide 40 and a carrierroller 41 that serve to carry the recording medium 4 also after pressingmeans of the pressure roller 3 with the recording medium in contact withor in close vicinity to the transfer drum 1. The carrier roller 41 ispressed by pressure applying means 42 and is separated from the transferdrum 1 by pressure release means 43. As shown in FIG. 13, the carrierguide 40 is provided with a notch window 50. Air is sent to the notchwindow 50 with a cooling fan 44 to cool the recording medium 6 from thereverse of the print face. This device is further provided with meansfor cooling the recording medium having a transferred ink image, that isa cooling roller 45. The cooling roller 45 may comprise a metal having agood heat conductivity or a hollow roller filled with a cooling medium.The cooling roller 45 can be also pressed by the pressure applying means46 and aparted from the transfer drum 1 by the pressure release means47. In this device, printing is effected as follows. Specifically, asdescribed above with reference to FIG. 12, firstly, the ink image formedon the transfer drum 1 by the recording head 2 is heated between thepressure roller 3 and the transfer drum 1 while the ink image is pressedagainst the recording medium 4, so that the ink image is brought to afilm form and simultaneously transferred to the recording medium 4.Thereafter, the recording medium 4 is carried with the rotation of thetransfer drum 1. The recording medium 4 is carried in contact with or inclose vicinity to the transfer drum 1 by the carrier guide 40 and thecarrier roller 41. During the carrying, the recording medium 4 is cooledby air sent from the cooling fan 44. Furthermore, the recording medium 4is cooled with a cooling roller 45 and finally separated from thetransfer drum 1 by a peeling claw 48.

In the recording method A according to the present invention, the inkimage on the transfer drum to the recording medium can be successfullytransferred under a low pressure of about 12 kg/cm or less, preferablyabout 10 kg/cm. When an ink composition containing a saccharideaccording to the preferred embodiment of the present invention isemployed, good transfer can be realized under a lower pressure than theabove, specifically a pressure of about 10 kg/cm or less, preferablyabout 0.6 kg/cm or less. A pressure of 0.6 kg/cm or less is veryadvantageous from a reduction in size of the device and a reduction incost of parts used.

The recording device B for the recording method B will now be described.As described above, some parts of the recording device B are the same asthat of the recording device A. Specifically, in the recording device B,the transfer drum 1, the recording head 2, the pressure roller 3, theheating means 5 and the cleaner means 7 may be the same as thosedescribed above in connection with the recording device A. Therefore,also in the devices shown in FIGS. 5 and 6, these parts may be the sameas those of the device shown in FIGS. 1 and 2. Furthermore, theembodiments shown in FIGS. 7 to 11 can be also utilized in the recordingdevice B.

The recording device B of the present invention and the recording deviceA are different from each other in that the recording device B hasheating means that can sufficiently concentrate the ink image on thetransfer drum 1 with the thermoplastic resin remaining unsoftened orunmelted. Thereafter, the ink image which has been concentrated andbrought to a film form by heating is then transferred to the recordingmedium 4.

A further difference between the recording device B of the presentinvention and the recording device A is that the recording device B hasmeans for heating the ink image transferred to the recording medium 4 toat least the softening or melting temperature of the thermoplasticresin, i.e., post-heating means. When the softening or meltingtemperature is between 50° C. and 150° C., the post heating is effectedin such a manner that the heating temperature is at least the softeningor melting temperature of the thermoplastic resin and preferably in therange of from 50° to 200° C., still preferably in the range of from 50°to 180° C.

In the devices shown in FIGS. 5 and 6, the roller 9b and the roller 9ccomprise, for example, a metal having a good heat conductivity.Furthermore, the heating element in the post-heating means may beconstructed, for example, as shown in FIG. 15. Specifically, therecording medium 4 having a transferred image is heated in a non-contactsystem with radiant heat from heating means 5 comprising a heater 52 anda reflecting mirror 53.

The recording method B according to the present invention, the ink imagecan be successfully transferred from the transfer drum to the recordingmedium under a low pressure of about 15 kg/cm or less, preferably 10kg/cm or less. Furthermore, when an ink composition containing asaccharide according to the preferred embodiment of the presentinvention is employed, good transfer can be realized under a lowerpressure than that described above, specifically about 10 kg/cm or less,preferably about 0.6 kg/cm or less.

In the step of post-heating in the recording method B according to thepresent invention, it is preferred to apply pressure simultaneously withheating although this is not essential to the present invention. Thepressure is specifically in the range of from about 0.3 to 1.5 kg/cm,preferably in the range of from about 0.3 to 0.8 kg/cm.

Ink Composition

According to the present invention, there is provided an ink compositionused in the above recording methods. As described above, in therecording method A, an ink composition comprising water, a colorant, athermoplastic resin is employed. In the recording method B, an inkcomposition comprising water, a colorant, a thermoplastic resin and awater-soluble organic solvent and, when the thermoplastic resin is awater-insoluble resin, further comprising a water-soluble polymer isemployed.

(Colorant)

The colorant used in the ink composition according to the presentinvention may preferably have a good affinity for the solvent or can behomogeneously dispersed in a solvent when it is used in combination witha dispersant.

Preferred examples of the colorant include water-soluble dyes, dispersedyes, water-insoluble dyes (when knead with a thermoplastic resin) andpigments.

Examples of the water-soluble dyes include direct dyes, acidic dyes,basic dyes and food dyes. Specific preferred examples thereof include:

C.I. Direct Black 9, 17, 19, 22, 32, 51, 56, 62, 69, 77, 80, 91, 94, 97,108, 112, 113, 114, 117, 118, 121, 122, 125, 132, 146, 154, 166, 168,173 and 199,

C.I. Direct Red 2, 4, 9, 23, 26, 31, 39, 62, 63, 72, 75, 76, 79, 80, 81,83, 84, 89, 92, 95, 111, 173, 184, 207, 211, 212, 214, 218, 221, 223,224, 225, 226, 227, 232, 233, 240, 241, 242, 243 and 247,

C.I. Direct Violet 7, 9, 47, 48, 51, 66, 90, 93, 94, 95, 98, 100 and101,

C.I Direct Yellow 8, 9, 11, 12, 27, 28, 29, 33, 35, 39, 41, 44, 50, 53,58, 59, 68, 86, 87, 93, 95, 96, 98, 100, 106, 108, 109, 110, 130, 132,142, 144, 161 and 163,

C.I. Direct Blue 1, 10, 15, 22, 25, 55, 67, 68, 71, 76, 77, 78, 80, 84,86, 87, 90, 98, 106, 108, 109, 151, 156, 158, 159, 160, 168, 189, 192,193, 194, 199, 200, 201, 202, 203, 207, 211, 213, 214, 218, 225, 229,236, 237, 244, 248, 249, 251, 252, 264, 270, 280, 288, 289 and 291, C.I.Acid Black 7, 24, 29, 48, 52:1 and 172,

C.I. Acid Red 35, 42, 52, 57, 62, 80, 82, 111, 114, 118, 119, 127, 128,131, 143, 151, 154, 158, 249, 254, 7, 261, 263, 266, 289, 299, 301, 305,336, 337, 361, 396 and 397,

C.I. Acid Violet 5, 34, 43, 47, 48, 90, 103 and 126,

C.I. Acid Yellow 17, 19, 23, 25, 39, 40, 42, 44, 49, 50, 61, 64, 76, 79,110, 127, 135, 143, 151, 159, 169, 4,190, 195, 196, 197,199, 218, 219,222 and 227,

C.I. Acid Blue 9, 25, 40, 41, 62, 72, 76, 78, 80, 82, 92, 106, 112, 113,120, 127:1, 129, 138, 143, 175, 181, 205, 207, 220, 221, 230, 232, 247,258, 260, 264, 271, 277, 278, 279, 280, 288, 290 and 326,

C.I. Reactive Black 4, 5, 8, 14, 21, 23, 26, 31, 32 and 34,

C.I. Reactive Red 3, 13, 17, 19, 21, 22, 23, 24, 29, 35, 37, 40, 41, 43,45, 49 and 55,

C.I. Reactive Violet 1, 3, 4, 5, 6, 7, 8, 9, 16, 17, 22, 23, 24, 26, 27,33 and 34,

C.I. Reactive Yellow 2, 3, 13, 14, 15, 17, 18, 23, 24, 25, 26, 27, 29,35, 37, 41 and 42,

C.I. Reactive Blue 2, 3, 5, 8, 10, 13, 14, 15, 17, 18, 19, 21, 25, 26,27, 28, 29 and 38,

C.I. Basic Black 8,

C.I. Basic Red 12, 13, 14, 15, 18, 22, 23, 24, 25, 27, 29, 35, 36, 38,39, 45 and 46,

C.I. Basic Violet 1, 2, 3, 7, 10, 15, 16, 20, 21, 25, 27, 28, 35, 37,39, 40 and 48,

C.I. Basic Yellow 1, 2, 4, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29,32, 36, 39 and 40,

C.I. Basic Blue 1, 3, 5, 7, 9, 22, 26, 41, 45, 46, 47, 54, 57, 60, 62,65, 66, 69 and 71, and

C.I. Food Black.

Specific preferred examples of the water-insoluble dye include:

C.I. Solvent Black 3, 5 and 22,

C.I. Solvent Yellow 19, 44, 98, 104, 105, 112, 113 and 114,

C.I. Solvent Red 8, 24, 71, 109, 152, 155, 176, 177 and 179,

C.I. Solvent Blue 2, 11, 25, 78, 94 and 95,

C.I. Solvent Green 26,

C.I. Solvent Orange 5, 40, 45, 72, 63, 68 and 78, and

C.I. Solvent Violet 13, 31, 32 and 33.

Preferred examples of the disperse dye include:

C.I. Disperse Yellow 3, 5, 56, 60, 64 and 160,

C.I. Disperse Red 4, 5, 60, 72, 73 and 91,

C.I. Disperse Blue 3, 7, 56, 60, 79 and 198, and

C.I. Disperse Orange 13 and 30.

The amount of these dyes added is determined depending upon, forexample, kinds of dyes, kinds of solvent component and propertiesrequired to the ink. It is generally in the range of 0.2 to 10% byweight, preferably in the range of 0.5 to 5% by weight.

The pigment usable as the colorant include organic pigments andinorganic pigments. Preferred specific examples of pigments for a blackink include carbon black (C.I. Pigment Black 7), such as furnace black,lamp black, acetylene black and channel black, metals, such as copper,iron (C.I. Pigment Black 11) and titanium oxide, and organic pigments,such as aniline black (C.I. Pigment Black 1). Preferred specificexamples of the pigment for a color ink include:

C.I. Pigment Yellow 1 (fast yellow G), 3 and 12 (disazo yellow AAA), 13,14, 17, 24, 34, 35, 37 and 42 (iron oxide yellow), 53, 55, 81 and 83(disazo yellow HR), 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120,138 and 153,

C.I. Pigment Orange 5, 13, 16, 17, 36, 43 and 51,

C.I. Pigment Red 1, 2, 3, 5, 17 and 22 (brilliant fast scarlet), 23, 31,38 and 48:2 (permanent red 2B (Ba)), 48:2 (permanent red 2B (Ca)), 48:3(permanent red 2B (Sr), 48:4 (permanent red 2B (Mn)), 49:1, 52:2, 53:1and 57:1 (brilliant carmine 6B), 60:1, 63:1, 63:2, 64:1 and 81(rhodamine 6G lake), 83, 88 and 101 (iron oxide red), 104, 105, 106 and108 (cadmium red), 112, 114 and 122 (quinacridone magenta), 123, 146,149,166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209 and 219,

C.I. Pigment Violet 1 (rhodamine lake), 3, 5:1, 16 and 19 (quinacridonered), 23 and 38,

C.I. Pigment Blue 1, 2 and 15 (phthalocyanine blue R), 15:1, 15:2 and15:3 (phthalocyanine blue G), 15:4 and 15:6 (phthalocyanine blue E), 16and 17:127 (iron blue), 28 (cobalt blue), 29 (ultramarine blue), 56, 60and 63, and

C.I. Pigment Green 1, 4, 7, 8, 10, 17, 18 and 36. It is also possible touse, besides the above pigments, processed pigments, such as graftcarbon having a surface treated with a resin or the like.

The amount of addition of the pigment is preferably about 1 to 30% byweight. The particle diameter of the pigment is preferably 25 μm orless, particularly preferably 1 μm or less.

If necessary, the addition of a dispersant in an amount of 1 to 100% byweight based on the pigment followed by a dispersion treatment with aball mill or the like may be carried out for the purpose ofhomogeneously dispersing the pigment.

(Thermoplastic Resin)

The thermoplastic resin used in the ink composition according to thepresent invention has a softening or hot-melt temperature of 50° to 150°C., preferably 60° to 100° C. The term "softening or meltingtemperature" used herein is intended to mean the lowest temperature inthe glass transition point, melting point, temperature necessary forproviding a coefficient of viscosity of 10¹¹ to 10¹² poises and fluidpoint.

The softening or melting point of the thermoplastic resin is under 50°C. may bring unfavorable phenomena, for example, when the ink is allowedto stand in an environment around 50° C., deterioration in the ink, suchas gelation of the ink, and clogging due to the formation of a resinfilm during drying within the ink jet head. On the other hand, when themelting temperature exceeds 150° C., the energy efficiency becomes poor.Furthermore, a material having heat resistance should be used, whichgives rise to problems such as an increase in cost of the device.

The amount of the thermoplastic resin used is preferably up to about 30%by weight based on the ink. These resins are preferably able to form asolid or a fragile solid matter without becoming a film form upon dryingat room temperature and, on the other hand, to form a strong andwater-resistant film upon heating at the softening or meltingtemperature or more followed by cooling.

Specific examples of the water-insoluble thermoplastic resin include,but not limited to, polyacrylic acid, polymethacrylic acid,polymethacrylic esters, polyethylacrylic acid, styrene/butadienecopolymer, butadiene copolymers, acrylonitrile/butadiene copolymer,chloroprene copolymer, crosslinked acrylic resin, crosslinked styreneresin, fluororesin, fluorinated vinylidene, benzoguanamine resin,phenolic resin, polyolefin resin, cellulose resin, styrene/acrylic acidcopolymer, styrene/methacrylic acid copolymer, polystyrene,styrene/acrylamide copolymer, n-isobutyl acrylate, acrylonitrile, vinylacetate, acrylamide, silicone resin, polyvinylacetal, polyamide, rosinresin, polyethylene, polycarbonate, vinylidene chloride resin,cellulosic resin, epoxy resin, vinyl acetate resin, ethylene/vinylacetate copolymer, vinyl acetate/acrylic copolymer, vinyl chlorideresin, polyurethane and rosin esters.

Specific examples of low-molecular weight thermoplastic resin includepolyethylene wax, montan wax, alcohol wax, synthesized oxidized wax,α-olefin/maleic anhydride copolymer, animal and vegetable waxes, such ascarnauba wax, lanolin, paraffin wax and microcrystalline wax.

These water-insoluble resins are added preferably in a form wherein theresin alone is dispersed as fine particles, or an emulsion particle formwherein the resin is stably dispersed in water (hereinafter oftenreferred to as "resin emulsion"). The resin emulsion added to the inkaccording to the present invention is intended to mean an emulsioncomprising water as a continuous phase and the above resin component asa disperse phase.

According to a preferred embodiment of the present invention, the resinconstituting the resin emulsion is preferably a polymer having acombination of a hydrophilic portion with a hydrophilic portion.Although the particle diameter of the resin component is notparticularly limited so far as the resin forms an emulsion, it ispreferably about 150 nm or less, still preferably about 5 to 100 nm.

The resin emulsion can be prepared by mixing resin particles optionallytogether with a surfactant in water. For example, an emulsion of anacrylic resin or a styrene-acrylic resin can be prepared by mixing a(meth)acrylic ester or styrene and a (meth)acrylic ester, optionallytogether with (meth)acrylic acid, and a surfactant into water. Thesurfactant is not particularly limited. Preferred examples thereofinclude anionic surfactants. They may be used alone or in the form of amixture of two or more of them.

Known resin emulsions may be used as the resin emulsion. For example,resin emulsions described in, for example, Japanese Patent PublicationNo. 1426/1987, Japanese Patent Laid-Open Nos. 56573/1991, 79678/1991,160068/1991 and 18462/1992, may be used.

Commercially available emulsions can also be utilized. Examples thereofinclude Microgel E-1002 and E-5002 (a styrene-acrylic resin emulsionmanufactured by Nippon Paint Co., Ltd.), Voncoat 4001 (an acrylic resinemulsion manufactured by Dainippon Ink and Chemicals, Inc.), Voncoat5454 (a styrene-acrylic resin emulsion manufactured by Dainippon ink andChemicals, Inc.), SAE1014 (a styrene-acrylic resin emulsion manufacturedby Nippon Zeon Co., Ltd.) and Saivinol SK-200 (an acrylic resin emulsionmanufactured by Saiden Chemical Industry Co., Ltd.).

In the ink composition according to the present invention, awater-soluble thermoplastic resin may be employed. Preferred examplesthereof include polyethylene oxide, glue, gelatin, casein, albumin, gumarabic, alginic acid, methyl cellulose, carboxymethyl cellulose,hydroxyethyl cellulose and polyvinyl ether.

In the ink composition according to the present invention, it is alsopossible to use particles of a colored resin comprising a thermoplasticresin integrated with a colorant. The colored resin particles may beprepared by mixing the thermoplastic resin with the colorant by meansof, e.g. a mixer, kneading the mixture by means of, e.g. a three-rollmill and granulating the kneaded product. The diameter of the coloredresin particles is preferably 10 μm or less, particularly preferably 5μm or less, from the viewpoint of preventing clogging of the recordinghead.

Commercially available colored resin particles may also be used, andexamples thereof include colored Microgel (manufactured by Nippon PaintCo., Ltd.) and toners for electrophotography.

(Water-Soluble Polymers)

The ink composition used in the recording method B may further comprisea water-soluble polymer, when the thermoplastic resin is awater-insoluble resin.

In the recording method B, the water-soluble polymer serves to bind thesolid component in the agglomerate which is formed by evaporating thesolvent from the ink and also serves to render the surface of theagglomerate viscose.

Preferred examples of the water-soluble polymer used in the presentinvention include polyalkyl oxides, such as polyethylene oxide,polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl butyral, polyacrylicacid, glue, gelatin, casein, albumin, gum arabic, alginic acid, methylcellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinylether, starch, polyethylene glycol and polyvinyl methyl ether.

The amount of the water-soluble polymer added is preferably in the rangeof from about 1 to 30% by weight, still preferably in the range of from1 to 20% by weight.

When the thermoplastic resin is soluble in water, since it serves to asa water-soluble polymer, the addition of a further water-soluble polymeris not indispensable. However, the addition thereof is preferred.

(Saccharides)

Examples of the saccharide used in the present invention includemonosaccharides, disaccharides, trisaccharides, tetrasaccharides,polysaccharides and their derivatives, such as reduction derivatives,oxidation derivatives, dehydration derivatives, amino acids,thiosaccharides and other saccharides.

Specific examples of the saccharide include glucose, diose, maltose,triose, tetrose, pentose, hexose, heptose, octose, nonose, sucrose,inositol, xylose, maltotriose, galactose, sugar alcohol, deoxy sugar,aldonic acid, uronic acid, glycoseen and α-cyclodextrin. Thepolysaccharide means saccharides in a broad sense and includes alsonaturally widely occurring substances such as dextrin and starch.

These saccharides are used in the ink in such an amount that the contentratio of the saccharide to the thermoplastic resin is in the range offrom 1:4 to 4:1.

(Solvent)

Water is used as the solvent in the ink composition according to thepresent invention. Water is particularly preferably pure water orultrapure water subjected to purification processes such as ion exchangeor distillation. Use of water as the solvent leads to advantagesincluding low viscosity, excellent safety, no fear of adverse effect onhuman body, easiness to handle, low cost and odorless.

The ink composition according to the present invention further comprisesa water-soluble organic solvent as the solvent. The addition of thewater-soluble organic solvent can improve the moisture retention of theink to prevent clogging and further improve the stability of the ink.Furthermore, the water-soluble organic solvent promotes the formation ofthe peeling layer. Without intending to be bound by theory, it isbelieved that the mechanism through which the "peeling layer" is formedis as follows. When the solid component (that is, composed mainly of acolorant and a resin component) contained in the ink composition has ahigh hydrophobicity, the solid component and the water-soluble organicsolvent are compatible with each other so far as water is present. Whenwater becomes absent, since the solid component is highly hydrophobicwith the water-soluble organic solvent being hydrophilic, the twocomponents become uncompatible with each other, which leads to a phaseseparation. Therefore, in the recording methods A and B according to thepresent invention, when the ink image is heated to form an agglomerateof the solid component, the water-soluble organic solvent isphase-separated from the solid component and bleeds out on theagglomerate, especially between the intermediate transfer medium and theagglomerate. The layer thus formed is considered to be a peeling layer.Accordingly, in order to efficiently form the peeling layer acombination of a solid component organic having a high hydrophobicityand a water-soluble solvent having a high hydrophilicity and a highboiling point (that is, less liable to evaporate) may be advantageous.

Preferred examples of the water-soluble organic solvent includenitrogen-containing organic solvents, such as polyhydric alcohols havinga high boiling point and a low volatility, such as glycerin, ethyleneglycol, diethylene glycol, triethylene glycol, propylene glycol,dipropylene glycol, hexylene glycol, polyethylene glycol andpolypropylene glycol. Further examples of the water-soluble organicsolvent include monoetherification products, dietherification productsand esterification products of the above-described polyhydric alcohols,such as ethylene glycol monomethyl ether, ethylene glycol monoethylether, ethylene glycol monobutyl ether, diethylene glycol monomethylether, diethylene glycol monoethyl ether and diethylene glycol monobutylether. Further preferred examples of the water-soluble organic solventinclude N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone,monoethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine,diethanolamine, N,N-butyldiethanolamine, triisopropanolamine andtriethanolamine. Further, when the main solvent is water, the additionof high volatile monohydric alcohols, such as ethanol, propanol,isopropanol and butanol, and relatively low volatile alcohols, such ashexanol, butanol and octanol, is preferred from the viewpoint ofimproving the quick drying property of the ink and the fixability. Thesewater-soluble organic solvents may be used alone or in any combinationof two or more of them.

The amount of these water-soluble organic solvents added is preferablyin the range of from about 2 to 30% by weight, still preferably in therange of from 3 to 15% by weight, based on the ink.

(Additives)

The ink composition of the present invention may further contain variousadditives.

For example, it is preferred to add at least one water-soluble anionic,cationic, amphoteric or nonionic surfactant to the ink composition ofthe present invention. The addition of the surfactant lowers the surfacetension of the ink. In this connection, when the surface of theintermediate transfer medium comprises, for example, a rubber materialhaving a low surface tension, the surfactant improves the wettability ofthe rubber material by the ink to prevent the occurrence of repellingand flow of the ink on the transfer medium, thus enabling the ink imageto be fixed.

Preferred specific examples of the anionic surfactant include a salt ofa higher fatty acid, a salt of a higher alkyldicarboxylic acid, a saltof a higher alcohol sulfuric acid ester, a salt of a higheralkylsulfonic acid, a salt of an alkylbenzenesulfonic acid, a salt of analkylnaphthalenesulfonic acid, a formalin condensate of a salt (Na, K,Li or Ca) of naphthalenesulfonic acid, a condensate of a higher fattyacid with an amino acid, a salt of an ester of a dialkylsulfosuccinicacid, a salt of an alkylsulfosuccinic acid, a salt of naphthalenic acid,a salt of an alkyl ether caboxylic acid, an acylated peptide, a salt ofan α-olefinsulfonic acid, N-acylated methyltaurine, a salt of analkylethersulfuric acid, a secondary higher alcohol ethoxysulfate, asalt of a polyoxyethylene alkylphenyl ether sulfonic acid, amonoglysulfate, a salt of an alkyl ether phosphoric acid ester and asalt of an alkylphosphoric acid ester.

Specific preferred examples of the cationic surfactant include a fattyacid amine salt, a quaternary ammonium salt, a sulfonium salt and aphosphonium salt.

Specific preferred examples of the amphoteric surfactant include acarboxybetaine type surfactant, a salt of aminocarboxylic acid andlecithin.

Specific preferred examples of the nonionic surfactant include afluorine surfactant, a silicone surfactant, a copolymer of acrylic acid,polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether,polyoxyethylene secondary alcohol ether, polyoxyethylene sterol ether, alanolin derivative of polyoxyethylene, an ethylene oxide derivative of aformalin condensate of an alkylphenol, apolyoxyethylene/polyoxypropylene block polymer, a fatty acid ester of apolyoxyethylene polyoxypropylene alkyl ether polyoxyethylene compound, apolyethylene oxide condensation type polyethylene glycol fatty acidester, a fatty acid monoglyceride, a polyglycerin fatty acid ester, asorbitan fatty acid ester, a propylene glycol fatty acid ester, asucrose fatty acid ester, a fatty acid alkanolamide, a polyoxyethylenefatty acid amide and a polyoxyethylene alkylamine oxide.

The amount of addition of these surfactants is preferably about 0.01 to10% by weight, still preferably about 0.1 to 5% by weight, based on theink.

In the ink composition of the present invention, if necessary, pHadjustors, such as potassium dihydrogenphosphate and disodiumhydrogenphosphate, benzoic acid, dichlorophene, hexachlorophene, sorbicacid, a p-hydroxybenzoic acid ester, ethylenediaminetetraacetic acid(EDTA), sodium dehydroacetate, 1,2-benzothiazolin-3-one,3,4-isothiazolin-3-one may be added as a fungicide, a preservative and arust preventive. Furthermore, urea, thiourea, ethyleneurea may be addedfor the purpose of preventing the nozzle from drying.

The viscosity of the ink composition of the present invention ispreferably 50 mPa-sec or less, particularly preferably 25 mPa-sec orless, from the viewpoint of ensuring stable ejection of the ink from thenozzle and stable supply of the ink to the head.

(Production of Ink Composition)

The ink composition of the present invention can be produced, forexample, by the following method. Specifically, a colorant,thermoplastic particles and optionally a dispersant (a surfactant), orthermoplastic colored resin particles and optionally a dispersant (asurfactant) are added to water, and they are mixed while stirring for 30min or more in a paint shaker or a ball mill until particles in theresultant dispersion are confirmed under a microscope to be in amonodisperse state. A water-soluble polymer, a water-soluble organicsolvent, a surfactant are added thereto, and mixing is further effectedwhile stirring for additional 30 min or more to provide a completelyhomogeneous mixture. Thereafter, additives, such as preservatives, areadded and completely dissolved therein. The mixture is filtered with afilter having a pore diameter of 20 to 5 μm to remove foreign particlesand coarse particles, thereby providing an ink composition.

EXAMPLES

Examples of the ink composition according to the present invention willnow be described in detail, though the present invention is not limitedto these Examples only.

In the following Examples, recording device (1) represents a deviceshown in FIG. 1, and recording device (2) represents a device shown inFIG. 5.

The composition ratio is % by weight unless otherwise noted.

EXAMPLE 1

    ______________________________________                                        Components          Composition ratio                                         ______________________________________                                        Ion-exchanged water 89.2                                                      Colorant            3.0                                                       (carbon black manufactured                                                    by Degussa)                                                                   Thermoplastic resin 2.0                                                       (PEO-1 manufactured by                                                        Sumitomo Chemical Engineering                                                 Co., Ltd., softening                                                          temp. = 65° C.)                                                        Dispersant (anionic surfactant)                                                                   0.8                                                       Water-soluble organic solvent                                                                     5.0                                                       (glycerin)                                                                    Total               100                                                       ______________________________________                                    

An ink composition was produced as follows. The colorant and thedispersant were added to the solvent and mixed together and stirred in apaint shaker for 1 hr until particles in the resultant dispersion wereconfirmed under a microscope to be in a monodisperse state. Thereafter,the thermoplastic resin was added thereto, and mixing was furthereffected for additional 1 hr to provide a homogeneous dispersion. Thedispersion was filtered with a filter having a pore diameter of 10 μm toprovide an ink composition.

When the ink composition was heated at 100° C. on a transfer drum of therecording device (1), the ink was able to be brought to a film form.

Comparative Example 1

The ink composition of Example 1 was put on the transfer drum of therecording device (1) at room temperature (25° C.) but not brought to afilm form.

EXAMPLE 2

    ______________________________________                                        Components          Composition ratio                                         ______________________________________                                        Ion-exchanged water 67.9                                                      Colored resin particles                                                                           20                                                        (colorant: carbon black;                                                      thermoplastic resin:                                                          styrene/acrylic copolymer)                                                    Dispersant (nonionic surfactant)                                                                  0.1                                                       Water-soluble organic solvent                                                                     7                                                         (glycerin)                                                                    Water-soluble organic solvent                                                                     5                                                         (ethanol)                                                                     Total               100                                                       ______________________________________                                    

The colored resin particles were prepared by kneading carbon black witha styrene/acrylic copolymer and granulating the kneaded product and hadan average particle diameter of 3.5 μm, a specific gravity of 1.1 and asoftening temperature of 86° C.

An ink was produced according to the following procedure. The coloredresin particles and the dispersant were stirred and mixed together inwater by means of a paint shaker for 30 min or more until particles inthe resultant dispersion were confirmed under a microscope to be in amonodisperse state. After glycerin was added thereto, the mixture wasstirred for additional 30 min for complete dissolution. The dispersionwas filtered with a membrane filter having a pore diameter of 20 μm toremove foreign particles and coarse particles. After ethanol was addedto the filtrate, they were mixed together for 5 min to provide arecording ink.

EXAMPLE 3

    ______________________________________                                        Components          Composition ratio                                         ______________________________________                                        Ion-exchanged water 72.9                                                      Colored resin particles                                                                           15                                                        (colored microgel)                                                            (colorant: anthraquinone                                                      black oil dye,                                                                thermoplastic resin: PMMA)                                                    Dispersant (nonionic surfactant)                                                                  0.1                                                       Water-soluble organic solvent                                                                     7                                                         (glycerin)                                                                    Water-soluble organic solvent                                                                     5                                                         (ethanol)                                                                     Total               100                                                       ______________________________________                                    

The colored resin particles comprised a colored microgel comprising aninternally three-dimensional crosslinked microgel and, incorporatedthereinto, a black oil dye and had an average particle diameter of 0.1μm, a specific gravity of 1.1 and a softening temperature of 96° C.

The ink was prepared in a similar manner as that of Example 2.

EXAMPLE 4

    ______________________________________                                        Components          Composition ratio                                         ______________________________________                                        Ion-exchanged water 67.9                                                      Colored resin particles                                                                           20                                                        (colorant: nonaqueous dye                                                     C.I. Solvent Violet 32;                                                       thermoplastic resin: Polystyrene)                                             Dispersant (nonionic surfactant)                                                                  0.1                                                       Water-soluble organic solvent                                                                     7                                                         (glycerin)                                                                    Water-soluble organic solvent                                                                     5                                                         (ethanol)                                                                     Total               100                                                       ______________________________________                                    

The colored resin particles were prepared by kneading C.I. SolventViolet 32 as an aqueous dye with polystyrene as a thermoplastic resinand granulating the kneaded product and had an average particle diameterof 8.5 μm, a specific gravity of 1.2 and a softening temperature of 73°C.

The ink was prepared in a similar manner as that of Example 2.

EXAMPLE 5

    ______________________________________                                        Component          Composition ratio                                          ______________________________________                                        Distilled water    72.5                                                       Colorant           10                                                         (organic pigment:                                                             phthalocyanine blue)                                                          Thermoplastic resin particles                                                                    5                                                          (polymethacrylic acid)                                                        Dispersant (fluorosurfactant)                                                                    0.5                                                        Water-soluble organic solvent                                                                    7                                                          (polyethylene glycol)                                                         Water-soluble organic solvent                                                                    5                                                          (propanol)                                                                    Total              100                                                        ______________________________________                                    

The thermoplastic resin particles had an average particle diameter of0.05 μm, a specific gravity of 1.19 and a softening temperature of 100°C.

An ink was produced according to the following procedure. The colorant,the thermoplastic resin particles and the dispersant were mixed togetherwith stirring in water by means of a paint shaker for 1 hr or more untilparticles in the resultant dispersion were confirmed under a microscopeto be in a monodisperse state. After polyethylene glycol was addedthereto, the mixture was further stirred for additional 30 min forcomplete dissolution. The dispersion was filtered with a membrane filterhaving a pore diameter of 5 μm to remove foreign particles and coarseparticles. After propanol was added to the filtrate, they were mixedtogether for 5 min to provide a recording ink.

EXAMPLE 6

    ______________________________________                                        Component           Composition ratio                                         ______________________________________                                        Distilled water     80.5                                                      Colorant            2                                                         (water-soluble dye:                                                           C.I. Acid Blue 9)                                                             Thermoplastic resin particles                                                                     5                                                         (PMMA)                                                                        Dispersant (nonionic surfactant)                                                                  0.5                                                       Water-soluble organic solvent                                                                     7                                                         (ethylene glycol)                                                             Water-soluble organic solvent                                                                     5                                                         (ethanol)                                                                     Total               100                                                       ______________________________________                                    

The thermoplastic resin particles had an average particle diameter of0.15 μm, a specific gravity of 1.1 and a softening temperature of 115°C.

The ink was prepared in a similar manner as that of Example 5.

EXAMPLE 7

    ______________________________________                                        Component            Composition ratio                                        ______________________________________                                        Distilled water      69.9                                                     Colorant             10                                                       (organic pigment:                                                             brilliant carmine 6B)                                                         Thermoplastic water-soluble resin                                                                  8                                                        (polyethylene oxide)                                                          Dispersant (anionic surfactant)                                                                    0.1                                                      Water-soluble organic solvent                                                                      7                                                        (triethylene glycol)                                                          Water-soluble organic solvent                                                                      5                                                        (ethanol)                                                                     Total                100                                                      ______________________________________                                    

The thermoplastic resin particles comprised a water-soluble resin andhad a softening temperature of 65° C.

An ink was prepared according to the following procedure. Thewater-soluble thermoplastic resin was mixed in water and stirred with apaint shaker for 1 hr or more (optionally while heating) until the resinwas completely dissolved in water. After the colorant and the dispersantwere added thereto, they were mixed together and stirred for additional1 hr until particles in the resultant dispersion were confirmed under amicroscope to be in a monodisperse state. After triethylene glycol wasadded thereto, the mixture was further stirred for additional 30 min tocompletely dissolve triethylene glycol. The dispersion was filtered witha membrane filter having a pore diameter of 5 μm to remove foreignparticles and coarse particles. After ethanol was added thereto, theywere mixed together for 5 min to provide the above recording ink.

EXAMPLE 8

    ______________________________________                                        Component            Composition ratio                                        ______________________________________                                        Distilled water      80.4                                                     Colorant             1.5                                                      (water-soluble dye:                                                           C.I. Acid Red 52)                                                             Thermoplastic water-soluble resin                                                                  6                                                        (polyvinyl ether)                                                             Dispersant (cationic surfactant)                                                                   0.1                                                      Water-soluble organic solvent                                                                      7                                                        (propylene glycol)                                                            Water-soluble organic solvent                                                                      5                                                        (ethanol)                                                                     Total                100                                                      ______________________________________                                    

The thermoplastic resin particles comprised a water-soluble resin andhad a softening temperature of 55° C.

The ink was prepared in a similar manner as that of Example 7.

EXAMPLE 9

    ______________________________________                                        Component           Composition ratio                                         ______________________________________                                        Distilled water     77.9                                                      Colorant            6                                                         (organic pigment:                                                             fast yellow G)                                                                Thermoplastic resin emulsion                                                                      6                                                         (polyacrylic acid)                                                            Dispersant (nonionic surfactant)                                                                  0.1                                                       Water-soluble organic solvent                                                                     7                                                         (water-soluble silicone oil)                                                  Water-soluble organic solvent                                                                     3                                                         (isopropanol)                                                                 Total               100                                                       ______________________________________                                    

The thermoplastic resin emulsion had a softening temperature of 93° C.and an average particle diameter of 0.15 μm. This emulsion was able tobe present at room temperature or above. In addition, at roomtemperature, while the emulsion dried, it is not able to be brought a"film form" but brought to soft or fragile.

An ink was prepared according to the following procedure. The colorant,the dispersant and the thermoplastic resin emulsion were mixed togetherand stirred in water by means of a paint shaker for 1 hr (optionallywhile heating). Therefore, it was confirmed that the resin wascompletely dissolved. After the colorant and the dispersant were addedthereto, they were mixed together and stirred for additional 1 hr. Thecolorant was confirmed under a microscope to be in a homogeneouslydispersed state. After water-soluble silicone oil was added thereto,they were further mixed together and stirred for additional 30 min tocompletely dissolve the silicone oil. The dispersion was filtered with amembrane filter having a pore diameter of 5 μm to remove foreignparticles and coarse particles. After iso-propanol was added thereto,and they were mixed together for 5 min to provide the above recordingink.

EXAMPLE 10

    ______________________________________                                        Component           Composition ratio                                         ______________________________________                                        Distilled water     80.9                                                      Colorant            2.5                                                       (water-soluble dye:                                                           Acid Yellow 23)                                                               Thermoplastic resin emulsion                                                                      4                                                         (carnauba wax)                                                                Dispersant (nonionic surfactant)                                                                  0.1                                                       Water-soluble organic solvent                                                                     6.5                                                       (glycerin)                                                                    Water-soluble organic solvent                                                                     6                                                         (ethanol)                                                                     Total               100                                                       ______________________________________                                    

The thermoplastic resin emulsion had a softening temperature of 68° C.and an average particle diameter of 0.1 μm. As the emulsion of Example9, at room temperature, while the emulsion dried, it is not able to bebrought a "film form" but brought to soft or fragile.

The ink was prepared in a similar manner as that of Example 9.

Comparative Example 2

    ______________________________________                                        Component           Composition ratio                                         ______________________________________                                        Distilled water     80.5                                                      Colorant (carbon black)                                                                           7                                                         Dispersant (nonionic dispersant)                                                                  0.5                                                       Water-soluble organic solvent                                                                     7                                                         (polyethylene glycol)                                                         Water-soluble organic solvent                                                                     5                                                         (ethanol)                                                                     Total               100                                                       ______________________________________                                    

The ink composition of this comparative example did not contain anythermoplastic resin component. The ink was prepared in a similar manneras that of Example 5.

Comparative Example 3

    ______________________________________                                        Component           Composition ratio                                         ______________________________________                                        Distilled water     75.5                                                      Colorant (carbon black)                                                                           7                                                         Nonthermoplastic resin particles                                                                  7                                                         (polyurethane particles)                                                      Dispersant (nonionic dispersant)                                                                  0.5                                                       Water-soluble organic solvent                                                                     5                                                         (polyethylene glycol)                                                         Water-soluble organic solvent                                                                     5                                                         (ethanol)                                                                     Total               100                                                       ______________________________________                                    

The ink composition of this comparative example contained a resincomponent not having a thermoplasticity (a thermosetting resin). The inkwas prepared in a similar manner as that of Example 5.

Comparative Example 4

    ______________________________________                                        Component             Composition ratio                                       ______________________________________                                        Distilled water       80.9                                                    Colorant              2.5                                                     (water-soluble dye:                                                           C.I. Direct Black 154)                                                        Thermoplastic resin emulsion                                                                        4                                                       (low-molecular weight polyethylene;                                           hot-melt temperature = 45° C.)                                         Dispersant (nonionic surfactant)                                                                    0.1                                                     Water-soluble organic solvent                                                                       6.5                                                     (glycerin)                                                                    Water-soluble organic solvent                                                                       6                                                       (ethanol)                                                                     Total                 100                                                     ______________________________________                                    

The ink composition of this comparative example contained athermoplastic resin having a melting temperature below 50° C. The inkwas prepared in a similar manner as that of Example 5.

EXAMPLE 11

    ______________________________________                                        Component          Composition ratio                                          ______________________________________                                        Ion-exchanged water                                                                              72.9                                                       Colored resin particles                                                                          20                                                         (colorant: carbon black;                                                      thermoplastic resin: styrene/                                                 acrylic copolymer)                                                            Dispersant (anionic surfactant)                                                                  0.1                                                        Water-soluble organic solvent                                                                    7                                                          (glycerin)                                                                    Total              100                                                        ______________________________________                                    

The colored resin particles were prepared by kneading carbon black witha styrene/acrylic copolymer and granulating the kneaded product and hadan average particle diameter of 3.5 μm, a specific gravity of 1.1 and asoftening temperature of 86° C.

An ink was produced according to the following procedure. The coloredresin particles and the dispersant were stirred and mixed together inwater by means of a paint shaker for 30 min or more until particles inthe resultant dispersion were confirmed under a microscope to be in amonodisperse state. After glycerin was added thereto, and mixing withstirring was effected for additional 30 min for complete dissolution.The dispersion was filtered with a membrane filter having a porediameter of 20 μm to remove foreign particles and coarse particles toprovide a recording ink.

EXAMPLE 12

    ______________________________________                                        Component           Composition ratio                                         ______________________________________                                        Ion-exchanged water 78.9                                                      Colored resin particles                                                                           15                                                        (Microgel manufactured by                                                     Nippon Paint Co., Ltd.)                                                       (colorant: anthraquinone                                                      black oil dye;                                                                thermoplastic resin:                                                          n-Butyl methacrylate)                                                         Dispersant (nonionic surfactant)                                                                  0.1                                                       Water-soluble organic solvent                                                                     1                                                         (glycerin)                                                                    Water-soluble organic solvent                                                                     5                                                         (ethanol)                                                                     Total               100                                                       ______________________________________                                    

The colored resin particles comprised a colored microgel comprising aninternally three-dimensional crosslinked microgel and, incorporatedthereinto, a black oil dye and had an average particle diameter of 0.1μm, a specific gravity of 1.1 and a softening temperature of 73° C.

An ink was produced according to the following procedure. The coloredresin particles and the dispersant were stirred and mixed together inwater by means of a paint shaker for 1 hr or more until the coloredresin particles were confirmed under a microscope to be in amonodisperse state. After glycerin was added thereto, the mixture wasstirred for additional 30 min for complete dissolution. The dispersionwas filtered with a membrane filter having a pore diameter of 5 μm toremove foreign particles and coarse particles. After propanol was addedto the filtrate, they were mixed together for 5 min to provide arecording ink.

EXAMPLE 13

    ______________________________________                                        Component           Composition ratio                                         ______________________________________                                        Distilled water     64.9                                                      Colorant (nonaqueous dye                                                                          20                                                        C.I. Solvent Violet 32;                                                       thermoplastic resin: polystyrene)                                             Dispersant (fluorosurfactant)                                                                     0.1                                                       Water-soluble organic solvent                                                                     10                                                        (ethylene glycol)                                                             Water-soluble organic solvent                                                                     5                                                         (propanol)                                                                    Total               100                                                       ______________________________________                                    

The colored resin particles had an average particle diameter of 0.05 μm,a specific gravity of 1.19 and a softening temperature of 73° C. The inkwas prepared in a similar manner as that of Example 12.

EXAMPLE 14

    ______________________________________                                        Component          Composition ratio                                          ______________________________________                                        Distilled water    54.5                                                       Colored resin particles                                                                          25                                                         (colorant: carbon black;                                                      thermoplastic resin: PMMA)                                                    Dispersant (fluorosurfactant)                                                                    0.5                                                        Water-soluble organic solvent                                                                    15                                                         (polyethylene glycol)                                                         Water-soluble organic solvent                                                                    5                                                          (ethanol)                                                                     Total              100                                                        ______________________________________                                    

The colored resin particles had an average particle diameter of 0.05 μm,a specific gravity of 1.19 and a softening temperature of 100° C. Theink was prepared in a similar manner as that of Example 12.

EXAMPLE 15

    ______________________________________                                        Component          Composition ratio                                          ______________________________________                                        Distilled water    42                                                         Colored resin particles                                                                          30                                                         (colorant: brilliant carmine 6B;                                              thermoplastic resin:                                                          polyethylene oxide)                                                           Dispersant (anionic surfactant)                                                                  3                                                          Water-soluble organic solvent                                                                    20                                                         (propylene glycol)                                                            Water-soluble organic solvent                                                                    5                                                          (ethanol)                                                                     Total              100                                                        ______________________________________                                    

The thermoplastic resin particles had an average particle diameter of0.15 μm, a specific gravity of 1.1 and a softening temperature of 120°C. The ink was prepared in a similar manner as that of Example 12.

EXAMPLE 16

    ______________________________________                                        Component          Composition ratio                                          ______________________________________                                        Distilled water    61                                                         Colored resin particles                                                                          20                                                         (colorant: carbon black;                                                      thermoplastic resin:                                                          styrene/acrylic copolymer)                                                    Dispersant (anionic surfactant)                                                                  3                                                          Water-soluble organic solvent                                                                    10                                                         (glycerin)                                                                    Water-soluble organic solvent                                                                    6                                                          (ethanol)                                                                     Total              100                                                        ______________________________________                                    

The thermoplastic resin particles comprised a toner forelectrophotography having an average particle diameter of 9 μm, aspecific gravity of 1.7 and a softening temperature of 120° C. The inkwas prepared in a similar manner as that of Example 11.

EXAMPLE 17

    ______________________________________                                        Component          Composition ratio                                          ______________________________________                                        Distilled water    62                                                         Colored resin particles                                                                          20                                                         (colorant: carbon black;                                                      thermoplastic resin:                                                          fumaric acid/etherified                                                       diphenolic polyester)                                                         Dispersant (anionic surfactant)                                                                  3                                                          Water-soluble organic solvent                                                                    10                                                         (glycerin)                                                                    Water-soluble organic solvent                                                                    5                                                          (ethanol)                                                                     Total              100                                                        ______________________________________                                    

The thermoplastic resin particles comprised a toner forelectrophotography having an average particle diameter of 7 μm, aspecific gravity of 1.6 and a softening temperature of 110° C. The inkwas prepared in a similar manner as that of Example 11.

Comparative Example 5

    ______________________________________                                        Component           Composition ratio                                         ______________________________________                                        Distilled water     80.9                                                      Colorant (carbon black)                                                                           7                                                         Dispersant (nonionic dispersant)                                                                  0.1                                                       Water-soluble organic solvent                                                                     7                                                         (polyethylene glycol)                                                         Water-soluble organic solvent                                                                     5                                                         (ethanol)                                                                     Total               100                                                       ______________________________________                                    

The ink composition of this comparative example did not contain anythermoplastic resin component.

An ink was produced according to the following procedure. The colorant,the thermoplastic resin particles and the dispersant were mixed togetherwith stirring in water by means of a paint shaker for 1 hr or more untilparticles in the resultant dispersion were confirmed under a microscopeto be in a monodisperse state. After polyethylene glycol was addedthereto, the mixture was-further stirred for additional 30 min forcomplete dissolution. The dispersion was filtered with a membrane filterhaving a pore diameter of 5 μm to remove foreign particles and coarseparticles. After ethanol was added to the filtrate, they were mixedtogether for 5 min to provide a recording ink.

Comparative Example 6

    ______________________________________                                        Component             Composition ratio                                       ______________________________________                                        Distilled water       74.9                                                    Colored resin particles                                                                             15                                                      (colorant: water-soluble dye:                                                 C.I. Direct Black 154                                                         thermoplastic resin emulsion:                                                 low-molecular weight polyethylene;                                            hot-melt temperature = 35° C.)                                         Dispersant (nonionic surfactant)                                                                    0.1                                                     Water-soluble organic solvent                                                                       5                                                       (glycerin)                                                                    Water-soluble organic solvent                                                                       5                                                       (ethanol)                                                                     Total                 100                                                     ______________________________________                                    

The ink composition of this comparative example contained athermoplastic resin component having a melting temperature below 50° C.The ink was prepared in a similar manner as that of Comparative Example5.

Comparative Example 7

    ______________________________________                                        Component           Composition ratio                                         ______________________________________                                        Distilled water     74.3                                                      Colored resin particles                                                                           15                                                        (colorant: water-soluble dye:                                                 C.I. Direct Black 154                                                         thermoplastic resin emulsion:                                                 high-molecular weight polyester;                                              hot-melt temperature = 165° C.)                                        Dispersant (nonionic surfactant)                                                                  0.3                                                       Water-soluble organic solvent                                                                     5                                                         (glycerin)                                                                    Water-soluble organic solvent                                                                     5                                                         (ethanol)                                                                     Total               100                                                       ______________________________________                                    

The ink composition of this comparative example contained athermoplastic resin component having a heat-softening temperature above150° C. The ink was prepared in a similar manner as that of ComparativeExample 5.

Comparative Example 8

    ______________________________________                                        Component          Composition ratio                                          ______________________________________                                        Ion-exchanged water                                                                              79.7                                                       Colored resin particles                                                                          20                                                         (colorant: carbon black;                                                      thermoplastic resin:                                                          styrene/acrylic copolymer)                                                    Dispersant (anionic surfactant)                                                                  0.3                                                        Water-soluble organic solvent                                                                    None                                                       (glycerin),                                                                   Total              100                                                        ______________________________________                                    

The ink composition of this comparative example did not contain anywater-soluble organic solvent. The procedure of Example 11 was repeatedto prepare an ink, except that only the step of adding the water-solubleorganic solvent was omitted.

EXAMPLE 18

    ______________________________________                                        Component          Composition ratio                                          ______________________________________                                        Ion-exchanged water                                                                              72                                                         Colored resin particles                                                                          20                                                         (colorant: carbon black)                                                      (thermoplastic resin:                                                         styrene/acrylic copolymer)                                                    Dispersant         1                                                          (silicone surfactant:                                                         Silwet L-7604 manufactured by                                                 Nippon Unicar Co., Ltd.)                                                      Water-soluble organic solvent                                                                    7                                                          (glycerin)                                                                    Total              100                                                        ______________________________________                                    

The colored resin particles were prepared by kneading carbon black witha styrene/acrylic copolymer and granulating the kneaded product and hadan average particle diameter of 3.5 μm, a specific gravity of 1.1 and asoftening temperature of 86° C.

An ink was produced according to the following procedure. The coloredresin particles and the dispersant were stirred and mixed together inwater by means of a paint shaker for 30 min or more until particles inthe resultant dispersion were confirmed under a microscope to in amonodisperse state. After glycerin was added thereto, the mixture wasstirred for additional 30 min for complete dissolution. The dispersionwas filtered with a membrane filter having a pore diameter of 20 μm toremove foreign particles and coarse particles to provide an ink.

EXAMPLE 19

    ______________________________________                                        Component              Composition ratio                                      ______________________________________                                        Ion-exchanged water    75                                                     Colored resin particles                                                                              15                                                     (colored microgel manufactured                                                by Nippon Paint Co., Ltd.)                                                    (colorant: anthraquinone                                                      black oil dye)                                                                (thermoplastic resin:                                                         n-Butyl methacrylate)                                                         Dispersant             1                                                      (anionic surfactant:                                                          trade name: AEROSOL OT-100;                                                   manufactured by Mitsui-Cyanamid, Ltd.)                                        Water-soluble organic solvent                                                                        9                                                      (triethylene glycol)                                                          Total                  100                                                    ______________________________________                                    

The colored resin particles comprised a colored microgel comprising aninternally three-dimensional crosslinked microgel and, incorporatedthereinto, a black oil dye and had an average particle diameter of 0.1μm, a specific gravity of 1.1 and a softening temperature of 50° C.

EXAMPLE 20

    ______________________________________                                        Component               Composition ratio                                     ______________________________________                                        Ion-exchanged water     64                                                    Colored resin particles 20                                                    (colorant: carbon black)                                                      (thermoplastic resin: fumaric                                                 acid/etherified diphenolic polyester)                                         Dispersant.             1                                                     (fluorosurfactant:                                                            trade name: FC-170C manufactured by                                           Sumitomo 3M Ltd.)                                                             Water-soluble organic solvent                                                                         5                                                     (polyethylene glycol)                                                         (glycerin)              5                                                     (ethanol)               5                                                     Total                   100                                                   ______________________________________                                    

The thermoplastic resin particles comprised a toner forelectrophotography having an average particle diameter of 7 μm, aspecific gravity of 1.6 and a softening temperature of 110° C. They canbe used in the ink for ink jet recording. The ink was prepared in asimilar manner as that of Example 18.

Comparative Example 9

    ______________________________________                                        Component          Composition ratio                                          ______________________________________                                        Ion-exchanged water                                                                              79                                                         Colored resin particles                                                                          20                                                         (colorant: carbon black)                                                      (thermoplastic resin:                                                         Styrene/acrylic copolymer)                                                    Dispersant         1                                                          (silicone surfactant:                                                         trade name: Silwet L-7604                                                     manufactured by                                                               Nippon Unicar Co., Ltd.)                                                      Total              100                                                        ______________________________________                                    

The ink composition of this comparative example did not contain anywater-soluble organic solvent. The thermoplastic resin is the same tonerfor electrophotography as that used in Example 20 and can be used in theink for ink jet recording according to the present invention. The inkwas prepared in a similar manner as that of Example 18.

EXAMPLE 21

    ______________________________________                                        Component               Composition ratio                                     ______________________________________                                        Colorant                15                                                    (20% water dispersion                                                         of carbon black)                                                              Thermoplastic resin     3                                                     (Styrene/acrylic copolymer:                                                   Microgel; resin emulsion                                                      manufactured by                                                               Nippon Paint Co., Ltd.)                                                       Water-soluble polymer   1.5                                                   (polyvinyl pyrrolidone)                                                       Surfactant              1                                                     (fluorosurfactant:                                                            Fluorad FC-170C;                                                              perfluoroalkylpolyoxyethylene ethanol                                         manufactured by Sumitomo 3M Ltd.)                                             Surfactant              1                                                     (sodium dioctylsulfosuccinate)                                                Water-soluble organic solvent                                                                         5                                                     (glycerin)                                                                    Ion-exchanged water     73.5                                                  Total                   100                                                   ______________________________________                                    

An ink was prepared according to the following procedure. After a waterdispersion of the colorant and the dispersant were mixed and confirmedunder a microscope to be in a monodisperse state, the water-solublepolymer, the thermoplastic resin, the surfactant and glycerin were addedthereto. They were mixed together and stirred for 30 min to provide acompletely homogeneous mixture. Thereafter, additives, such as apreservative, were added and completely dissolved therein. Thedispersion was filtered with a membrane filter having a pore diameter of10 μm to remove foreign particles and coarse particles to provide arecording ink.

The thermoplastic resin had an internal three-dimensional crosslinkingand a particle diameter of 0.2 μm and a softening point of 65° C. The20% water dispersion of carbon black was prepared by dissolving adispersant (sodium dioctylsulfosuccinate) in a ratio of the dispersantto the pigment (MA-100 manufactured by Mitsubishi Kasei Corp.) of 0.1 inpure water, adding the pigment in the solution, and dispersing thepigment in an average particle diameter of 0.5 μm by means of a ballmill.

EXAMPLE 22

    ______________________________________                                        Component            Composition ratio                                        ______________________________________                                        Colorant             15                                                       (20% water dispersion of                                                      carbon black: prepared as                                                     described in Example 30)                                                      Thermoplastic resin  5                                                        (polyacrylic ester:                                                           Primal manufactured by                                                        Japan Acrylic Chemical Co., Ltd.)                                             Water-soluble polymer                                                                              5                                                        (carboxymethyl cellulose)                                                     Surfactant           2                                                        (fluorosurfactant: Fluorad FC-430;                                            fluoroalkyl ester manufactured by                                             Sumitomo 3M Ltd.)                                                             Water-soluble organic solvent                                                                      7                                                        (dipropylene glycol)                                                          Sodium dehydroacetate                                                                              0.1                                                      Ion-exchanged water  65.9                                                     Total                100                                                      ______________________________________                                    

The ink was prepared in a similar manner as that of Example 21. Thethermoplastic resin had a softening point of 86° C.

EXAMPLE 23

    ______________________________________                                        Component               Composition ratio                                     ______________________________________                                        Colorant + thermoplastic                                                                              10                                                    resin (toner for                                                              electrophotography                                                            containing carbon black and                                                   styrene/acrylic copolymer)                                                    Water-soluble polymer   5                                                     (polyvinyl alcohol)                                                           Surfactant              1                                                     (silicone surfactant: Silwet L-7604                                           manufactured by Nippon Unicar Co., Ltd.)                                      Surfactant              1                                                     (fluorosurfactant:                                                            Fluorad FC-170; fluoroalkyl ester                                             manufactured by Sumitomo 3M Ltd.)                                             Water-soluble organic solvent                                                                         5                                                     (ethylene glycol)                                                             Water-soluble organic solvent                                                                         5                                                     (ethanol)                                                                     Ethylenediaminetetraacetic acid                                                                       0.1                                                   (EDTA)                                                                        Ion-exchanged water     72.9                                                  Total                   100                                                   ______________________________________                                    

An ink was prepared according to the following procedure. The toner, thesurfactant and ethylene glycol were mixed together in a ball mill or apaint shaker until the toner was confirmed under a microscope to be in amonodisperse state. After the water-soluble polymer and ethanol wereadded thereto, the mixture was further stirred for additional 30 min toprovide a completely homogeneous mixture. Thereafter, additives, such asa preservative, were added and completely dissolved therein. Thedispersion was then filtered with a membrane filter having a porediameter of 20 μm to remove foreign particles and coarse particles toprovide a recording ink.

The toner used had a particle diameter of 7 μm and a softeningtemperature of 90° C.

EXAMPLE 24

    ______________________________________                                        Component            Composition ratio                                        ______________________________________                                        Colorant             15                                                       (20% water dispersion of                                                      carbon black: prepared as                                                     described in Example 21)                                                      Thermoplastic water-soluble resin                                                                  5                                                        (polyethylene oxide)                                                          Surfactant           3                                                        (fluorosurfactant:                                                            Fluorad FC-170C;                                                              perfluoroalkylpolyoxyethylene                                                 ethanol manufactured by                                                       Sumitomo 3M Ltd.)                                                             Surfactant           3                                                        (sodium dioctylsulfosuccinate)                                                Water-soluble organic solvent                                                                      5                                                        (polyethylene glycol #200)                                                    Ion-exchanged water  69                                                       Total                100                                                      ______________________________________                                    

The procedure of Example 21 was repeated to prepare an ink. The aboveresin had a combination of the properties of the thermoplastic resinwith the effect of the water-soluble polymer and a softening temperatureof 60° C.

EXAMPLE 25

An ink was prepared in a similar manner as that of Example 21, exceptthat phthalocyanine blue as a color organic pigment was used.

EXAMPLE 26

    ______________________________________                                        Component              Composition ratio                                      ______________________________________                                        Colorant               1.5                                                    (water-soluble dye:                                                           C.I. Direct Black 9)                                                          Thermoplastic resin    5                                                      (ethylene/vinyl acetate                                                       copolymer: resin emulsion manufactured                                        by Denki Kagaku Kogyo K.K.)                                                   Water-soluble polymer  5                                                      (water-soluble acrylic resin:                                                 Primal P-6N manufactured by                                                   Japan Acrylic Chemical Co., Ltd.                                              Surfactant             1                                                      (nonionic surfactant:                                                         Sorgen TW-60 polyoxyethylene                                                  sorbitan monostearate manufactured                                            by Dai-ichi Kogyo Seiyaku Co., Ltd.)                                          Water-soluble organic solvent                                                                        5                                                      (triethanolamine)                                                             Water-soluble organic solvent                                                                        5                                                      (Propanol)                                                                    Sodium dehydroacetate  0.1                                                    Ion-exchanged water    77.4                                                   Total                  100                                                    ______________________________________                                    

An ink was prepared according to the following procedure. Thewater-soluble dye, the surfactant, diethylene glycol and theion-exchanged water were mixed together in a paint shaker until the dyewas confirmed under a microscope to be in a monodisperse state. Afterthe thermoplastic resin, the water-soluble polymer, the surfactant andpropanol were added thereto, the mixture was further stirred foradditional 30 min to provide a completely homogeneous mixture.Thereafter, additives, such as a preservative, were added and completelydissolved therein. The dispersion was then filtered with a membranefilter having a pore diameter of 50 μm to remove foreign particles andcoarse particles to provide a recording ink. The thermoplastic resin hada softening temperature of 82° C.

Comparative Example 10

The ink was prepared in a similar manner as that of Example 21, exceptthat the thermoplastic resin was not added.

Comparative Example 11

The ink was prepared in a similar manner as that of Example 21, exceptthat the water-soluble polymer was not added.

Comparative Example 12

The ink was prepared in a similar manner as that of Example 21, exceptthat the thermoplastic resin (a styrene/acrylic copolymer) used had asoftening point of 36° C.

Comparative Example 13

The ink was prepared in a similar manner as that of Example 30, exceptthat the thermoplastic resin (a styrene/acrylic copolymer) used had asoftening point of 180° C.

EXAMPLE 27

    ______________________________________                                        Component               Composition ratio                                     ______________________________________                                        Colorant + thermoplastic                                                                              10                                                    resin (toner for                                                              electrophotography                                                            containing carbon black and                                                   styrene/acrylic copolymer)                                                    Water-soluble polymer   5                                                     (polyvinyl alcohol:                                                           trade name: Denka Poval manufactured by                                       Denki Kagaku Kogyo K.K.,                                                      molecular weight: about 40,000)                                               Surfactant              1                                                     (silicone surfactant:                                                         trade name: Silwet L-7604 manufactured by                                     Nippon Unicar Co., Ltd.)                                                      Surfactant              1                                                     (fluorosurfactant:                                                            trade name: Fluorad FC-170;                                                   fluoroalkyl ester                                                             manufactured by Sumitomo 3M Ltd.)                                             Water-soluble organic solvent                                                                         5                                                     (ethylene glycol)                                                             Water-soluble organic solvent                                                                         5                                                     (ethanol)                                                                     Ethylenediaminetetraacetic acid                                                                       0.1                                                   (EDTA)                                                                        Ion-exchanged water     72.9                                                  Total                   100                                                   ______________________________________                                    

An ink was prepared according to the following procedure. The toner, thesurfactant and ethylene glycol were mixed together in a ball mill or apaint shaker until the toner was confirmed under a microscope to be in amonodisperse state. After the water-soluble polymer and ethanol wereadded thereto, the mixture was further stirred for additional 30 min toprovide a completely homogeneous mixture. Thereafter, additives, such asa preservative, were added and completely dissolved therein. Thedispersion was then filtered with a membrane filter having a porediameter of 20 μm to remove foreign particles and coarse particles toprovide a recording ink.

The toner used had a particle diameter of 7 μm and a softeningtemperature of 90° C.

EXAMPLE 28

    ______________________________________                                        Component             Composition ratio                                       ______________________________________                                        Colorant + thermoplastic                                                                            10                                                      resin (toner for                                                              electrophotography                                                            containing carbon black and                                                   styrene/acrylic copolymer)                                                    Water-soluble polymer 5                                                       (polyvinyl pyrrolidone:                                                       manufactured by                                                               Tokyo Chemical Industry Co., Ltd.,                                            molecular weight: about 40,000)                                               Surfactant            1                                                       (silicone surfactant:                                                         trade name: Silwet L-7604                                                     manufactured by                                                               Nippon Unicar Co., Ltd.)                                                      Surfactant            1                                                       (fluorosurfactant:                                                            trade name: Fluorad FC-170;                                                   fluoroalkyl ester                                                             manufactured by Sumitomo 3M Ltd.)                                             Water-soluble organic solvent                                                                       5                                                       (ethylene glycol)                                                             Water-soluble organic solvent                                                                       5                                                       (ethanol)                                                                     Ethylenediaminetetraacetic acid                                                                     0.1                                                     (EDTA)                                                                        Ion-exchanged water   72.9                                                    Total                 100                                                     ______________________________________                                    

The ink was prepared in a similar manner as that of Example 27.

The toner used had a particle diameter of 3 μm and a softeningtemperature of 65° C.

EXAMPLE 29

    ______________________________________                                        Component             Composition ratio                                       ______________________________________                                        Colorant + thermoplastic                                                                            10                                                      resin (toner: toner for                                                       electrophotography)                                                           Water-soluble polymer 5                                                       (water-soluble acrylic resin:                                                 trade name: Primal                                                            manufactured by                                                               Japan Acrylic Chemical Co., Ltd.)                                             Surfactant.           1                                                       (silicone surfactant:                                                         trade name: Silwet L-7604                                                     manufactured by                                                               Nippon Unicar Co., Ltd.)                                                      Surfactant            1                                                       (fluorosurfactant:                                                            trade name: Fluorad FC-170;                                                   fluoroalkyl ester                                                             manufactured by Sumitomo 3M Ltd.)                                             Water-soluble organic solvent                                                                       5                                                       (ethylene glycol)                                                             Water-soluble organic solvent                                                                       5                                                       (ethanol)                                                                     Ethylenediaminetetraacetic acid                                                                     0.1                                                     (EDTA)                                                                        Ion-exchanged water   72.9                                                    Total                 100                                                     ______________________________________                                    

The ink was prepared in a similar manner as that of Example 27.

The toner used had a particle diameter of 2.5 μm and a softeningtemperature of 90° C.

EXAMPLE 30

    ______________________________________                                        Component               Composition ratio                                     ______________________________________                                        Colorant                2                                                     (carbon black: MA-100 manufactured by                                         Mitsubishi Kasei Corp.)                                                       Thermoplastic resin     8                                                     (styrene-n-Butyl methacrylate                                                 copolymer: Himer SBM-73 manufactured by                                       Sanyo Chemical Industry Co., Ltd.)                                            Water-soluble polymer   5                                                     (polyvinyl alcohol: trade name:                                               Denka Poval manufactured by                                                   Denki Kagaku Kogyo K.K.,                                                      molecular weight: about 40,000)                                               Surfactant              1                                                     (silicone surfactant:                                                         trade name: Silwet L-7604 manufactured by                                     Nippon Unicar Co., Ltd.)                                                      Surfactant              1                                                     (fluorosurfactant:                                                            trade name: Fluorad FC-170;                                                   fluoroalkyl ester manufactured by                                             Sumitomo 3M Ltd.)                                                             Water-soluble organic solvent                                                                         5                                                     (ethylene glycol)                                                             Water-soluble organic solvent                                                                         5                                                     (ethanol)                                                                     Ethylenediaminetetraacetic acid                                                                       0.1                                                   (EDTA)                                                                        Ion-exchanged water     72.9                                                  Total                   100                                                   ______________________________________                                    

An ink was prepared according to the following procedure. The carbonblack and the thermoplastic resin were mixed together by means of amixer, kneaded at 90° C. or below by means of a three-roll mill, cooledand subjected to coarse crushing to provide coarse particles of acolored resin. The coarse particles, water, the surfactant and ethyleneglycol were mixed together by means of a ball mill to disperse thecolored resin particles. After the particles were confirmed under amicroscope to be in a fine monodisperse state, the water-soluble polymerand ethanol were added thereto. The mixture was further stirred foradditional 30 min to provide a completely homogeneous mixture.Thereafter, additives, such as a preservative, were added and completelydissolved therein. The dispersion was then filtered with a membranefilter having a pore diameter of 20 μm to remove foreign particles andcoarse particles to provide a recording ink.

The toner used had a particle diameter of 5 μm and a softeningtemperature of 65° C.

Comparative Example 14

The composition was the same as that of Example 27, except that thethermoplastic resin was not added.

    ______________________________________                                        Component               Composition ratio                                     ______________________________________                                        Colorant                15                                                    (20% water dispersion                                                         of carbon black)                                                              Water-soluble polymer   5                                                     (polyvinyl alcohol:                                                           trade name: Denka Poval manufactured by                                       Denki Kagaku Kogyo K.K.,                                                      molecular weight: about 40,000)                                               Surfactant              1                                                     (sodium dioctylsulfosuccinate)                                                Surfactant              1                                                     (fluorosurfactant:                                                            trade name: Fluorad FC-170; fluoroalkyl ester                                 manufactured by Sumitomo 3M Ltd.)                                             Water-soluble organic solvent                                                                         5                                                     (ethylene glycol)                                                             Water-soluble organic solvent                                                                         5                                                     (ethanol)                                                                     Ethylenediaminetetraacetic acid                                                                       0.1                                                   (EDTA)                                                                        Ion-exchanged water     67.9                                                  Total                   100                                                   ______________________________________                                    

An ink was prepared according to the following procedure. After a waterdispersion comprising the colorant and the dispersant was confirmedunder a microscope to be in a monodisperse state, the water-solublepolymer, surfactant and ethylene glycol were added thereto. The mixturewas further stirred for additional 30 min to provide a completelyhomogeneous mixture. Thereafter, additives, such as a preservative, wereadded and completely dissolved therein. The dispersion was then filteredwith a membrane filter having a pore diameter of 10 μm to remove foreignparticles and coarse particles to provide a recording ink. The 20% waterdispersion of carbon black was prepared by dissolving a dispersant(sodium dioctylsulfosuccinate) in a ratio of the dispersant to thepigment (MA-100 manufactured by Mitsubishi Kasei Corp.) of 0.1 in purewater, adding the pigment in the solution, and dispersing the pigment inan average particle diameter of 0.5 μm by means of a ball mill.

The average particle diameter of the carbon black was 0.5 μm.

Comparative Example 15

The ink was prepared in a similar manner as that of Example 27, exceptthat the water-soluble polymer was not added.

EXAMPLE 31

    ______________________________________                                        Component              Composition ratio                                      ______________________________________                                        Colorant               15                                                     (20 wt. % water dispersion                                                    of carbon black)                                                              Thermoplastic resin    15                                                     (20 wt. % water dispersion                                                    of ultrafine particles microgel                                               of polymer having                                                             three-dimensional structure:                                                  manufactured by Nippon Paint Co., Ltd.,                                       softening temp. = 65° C.;                                              particle diameter: 0.50 μm)                                                Water-soluble polymer  1.5                                                    (polyvinyl alcohol:                                                           Denka Poval manufactured by                                                   Denki Kagaku Kogyo K.K.)                                                      Surfactant             1                                                      (silicone surfactant:                                                         Silwet L-7604 manufactured by                                                 Nippon Unicar Co., Ltd.)                                                      Water-soluble organic solvent                                                                        5                                                      (dipropylene glycol)                                                          Ion-exchanged water    62.5                                                   Total                  100                                                    ______________________________________                                    

An ink was prepared according to the following procedure.

After a water dispersion comprising the colorant and the dispersant wasconfirmed under a microscope to be in a monodisperse state, thesurfactant, dipropylene glycol, the water-soluble polymer and the waterdispersion of ultrafine particles of a polymer having athere-dimensional crosslinked structure were added thereto. The mixturewas further stirred for additional 30 min to provide a completelyhomogeneous mixture. Thereafter, additives, such as a preservative, wereadded and completely dissolved therein. The dispersion was then filteredwith a membrane filter having a pore diameter of 10 μm to remove foreignparticles and coarse particles to provide a recording ink. The 20% waterdispersion of carbon black was prepared by dissolving a dispersant(sodium dioctylsulfosuccinate) in a ratio of the dispersant to thepigment (#1000 manufactured by Mitsubishi Kasei Corp.) of 0.1 in purewater, adding the pigment in the solution and dispersing the pigment inan average particle diameter of 0.5 μm by means of a ball mill.

EXAMPLE 32

    ______________________________________                                                                  Composition                                         Component                 ratio                                               ______________________________________                                        Colorant                  15                                                  (20 wt. % water dispersion of carbon black:                                   prepared as described in Example 31)                                          Thermoplastic resin       15                                                  (20 wt. % water dispersion of ultrafine particles                             microgel of polymer having three-dimensional                                  structure: manufactured by Nippon Paint Co., Ltd.,                            softening temp. = 90° C.;                                              particle diameter: 0.07 μm)                                                Water-soluble polymer     1.5                                                 (polyvinyl alcohol: Denka Poval manufactured by                               Denki Kagaku Kogyo K.K.)                                                      Surfactant                1                                                   (silicone surfactant: Silwet L-7604 manufactured by                           Nippon Unicar Co., Ltd.)                                                      Water-soluble organic solvent                                                                           5                                                   (dipropylene glycol)                                                          Ion-exchanged water       62.5                                                Total                     100                                                 ______________________________________                                    

The ink was prepared in a similar manner as that of Example 31.

EXAMPLE 33

    ______________________________________                                                                  Composition                                         Component                 ratio                                               ______________________________________                                        Colorant                  15                                                  (20 wt. % water dispersion of carbon black:                                   prepared as described in Example 31)                                          Thermoplastic resin       15                                                  (20 wt. % water dispersion of ultrafine particles                             microgel of polymer having three-dimensional                                  structure: manufactured by Nippon Paint Co., Ltd.,                            softening temp. = 110° C.;                                             particle diameter: 0.85 μm)                                                Water-soluble polymer     1.5                                                 (polyvinyl alcohol: Denka Poval manufactured by                               Denki Kagaku Kogyo K.K.)                                                      Surfactant                1                                                   (silicone surfactant: Silwet L-7604 manufactured by                           Nippon Unicar Co., Ltd.)                                                      Water-soluble organic solvent                                                                           5                                                   (dipropylene glycol)                                                          Ion-exchanged water       62.5                                                Total                     100                                                 ______________________________________                                    

The ink was prepared in a similar manner as that of Example 31.

EXAMPLE 34

    ______________________________________                                                                  Composition                                         Component                 ratio                                               ______________________________________                                        Colorant                  15                                                  (20 wt. % water dispersion of carbon black:                                   prepared as described in Example 31)                                          Thermoplastic resin       40                                                  (20 wt. % water dispersion of ultrafine particles                             microgel of polymer having three-dimensional                                  structure: manufactured by Nippon Paint Co., Ltd.,                            softening temp. = 65° C.;                                              particle diameter: 0.50 μm)                                                Water-soluble polymer     1.5                                                 (polyvinyl alcohol: Denka Poval manufactured by                               Denki Kagaku Kogyo K.K.)                                                      Surfactant                1                                                   (silicone surfactant: Silwet L-7604 manufactured by                           Nippon Unicar Co., Ltd.)                                                      Water-soluble organic solvent                                                                           5                                                   (dipropylene glycol)                                                          Ion-exchanged water       37.5                                                Total                     100                                                 ______________________________________                                    

The ink was prepared in a similar manner as that of Example 31.

EXAMPLE 35

    ______________________________________                                                                  Composition                                         Component                 ratio                                               ______________________________________                                        Colorant                  15                                                  (20 wt. % water dispersion of carbon black:                                   prepared as described in Example 40)                                          Thermoplastic resin       15                                                  (20 wt. % water dispersion of ultrafine particles                             microgel of polymer having three-dimensional                                  structure: manufactured by Nippon Paint Co., Ltd.,                            softening temp. = 65° C.;                                              particle diameter: 0.50 μm)                                                Water-soluble polymer     1.5                                                 (Polyvinyl pyrrolidone: manufactured by                                       Tokyo Chemical Industry Co., Ltd.)                                            Water-soluble polymer     1                                                   (polyvinyl alcohol: Denka Poval manufactured by                               Denki Kagaku Kogyo K.K.)                                                      Surfactant                1                                                   (silicone surfactant: Silwet L-7604 manufactured by                           Nippon Unicar Co., Ltd.)                                                      Water-soluble organic solvent                                                                           5                                                   (dipropylene glycol)                                                          Ion-exchanged water       61.5                                                Total                     100                                                 ______________________________________                                    

The ink was prepared in a similar manner as that of Example 31.

EXAMPLE 36

    ______________________________________                                                                  Composition                                         Component                 ratio                                               ______________________________________                                        Colorant                  15                                                  (20 wt. % water dispersion of carbon black:                                   prepared as described in Example 31)                                          Thermoplastic resin       15                                                  (20 wt. % water dispersion of ultrafine particles                             microgel of polymer having three-dimensional                                  structure: manufactured by Nippon Paint Co., Ltd.,                            softening temp. = 65° C.;                                              particle diameter: 0.50 μm)                                                Water-soluble polymer     2.5                                                 (Polyvinyl pyrrolidone: manufactured by                                       Tokyo Chemical Industry Co., Ltd.)                                            Surfactant                1                                                   (silicone surfactant: Silwet L-7604 manufactured by                           Nippon Unicar Co., Ltd.)                                                      Water-soluble organic solvent                                                                           5                                                   (dipropylene glycol)                                                          Ion-exchanged water       61.5                                                Total                     100                                                 ______________________________________                                    

The ink was prepared in a similar manner as that of Example 31.

Comparative Example 16

The ink was prepared in a similar manner as that of Example 31, exceptthat the thermoplastic resin was not added.

Comparative Example 17

The ink was prepared in a similar manner as that of Example 31, exceptthat the water-soluble resin was not added.

Comparative Example 18

The ink was prepared in a similar manner as that of Example 31, exceptthat the thermoplastic resin used was a microgel having athree-dimensional crosslinked structure and had a softening temperatureof 36° C.

Comparative Example 19

The ink was prepared in a similar manner as that of Example 31, exceptthat the thermoplastic resin used was a microgel having athree-dimensional crosslinked structure and had a softening temperatureof 180° C.

EXAMPLE 37

    ______________________________________                                                                  Composition                                         Component                 ratio                                               ______________________________________                                        Colorant                  20.0                                                (15% water dispersion of carbon black: pigment:                               MA-100 manufactured by Mitsubishi Kasei Corp.)                                Thermoplastic resin       10.0                                                (styrene/acrylic copolymer: Microgel: resin                                   emulsion manufactured by Nippon Paint Co., Ltd.)                              Sugar (α-cyclodextrin)                                                                            10.0                                                Water-soluble organic solvent                                                                           9.0                                                 (dipropylene glycol)                                                          Preservative              0.01                                                (Ethylenediaminetetraacetic acid)                                             Ion-exchanged water       50.99                                               Total                     100                                                 ______________________________________                                    

The 15% water dispersion of carbon black as the colorant was prepared bydissolving a dispersant (sodium dioctylsulfosuccinate) in a ratio of thedispersant to the pigment of 0.1 in pure water, adding the pigment inthe solution and dispersing the pigment in an average particle diameterof 0.5 μm by means of a ball mill.

An ink was prepared according to the following procedure. The colorantand the dispersant were dispersed in the solvent. After the dispersoidwas confirmed under a microscope to be in a monodisperse state, thesaccharide, the thermoplastic resin and dipropylene glycol were addedthereto. The mixture was further stirred for additional 30 min toprovide a completely homogeneous mixture. Thereafter, additives, such asa preservative, were added and completely dissolved therein. Thedispersion was then filtered with a membrane filter having a porediameter of 10 μm to remove foreign particles and coarse particles toprovide a recording ink.

The thermoplastic resin used herein had an internally three-dimensionalcrosslinked structure, a particle diameter of about 0.2 μm and asoftening temperature of 65° C.

EXAMPLE 38

    ______________________________________                                                                  Composition                                         Component                 ratio                                               ______________________________________                                        Colorant                  20.0                                                (15% water dispersion of carbon black:                                        prepared as described in Example 37)                                          Thermoplastic resin       10.0                                                (Superflex: crosslinked urethane elastomer resin                              emulsion manufactured by Dai-Ichi Kogyo Seiyaku                               Co., Ltd.)                                                                    Sugar (sucrose)           10.0                                                Water-soluble organic solvent                                                                           9.0                                                 (diethylene glycol)                                                           Surfactant                1.0                                                 (fluorosurfactant: Fluorad FC-170C; fluoroalkyl                               ester manufactured by Sumitomo 3M Ltd.)                                       Ion-exchanged water       50.0                                                Total                     100                                                 ______________________________________                                    

The ink was prepared in a similar manner as that of Example 37. Thethermoplastic resin used had a particle diameter of about 0.5 μm and asoftening point of 80° C.

EXAMPLE 39

    ______________________________________                                                                  Composition                                         Component                 ratio                                               ______________________________________                                        Colorant                  20.0                                                (15% water dispersion of carbon black:                                        prepared as described in Example 37)                                          Thermoplastic resin       10.0                                                (Primal manufactured by Japan Acrylic Chemical                                Co., Ltd.)                                                                    Sugar (starch)            10.0                                                Water-soluble organic solvent                                                                           4.5                                                 (diethylene glycol)                                                           Water-soluble organic solvent                                                                           4.5                                                 (ethyl alcohol)                                                               Surfactant                3.0                                                 (fluorosurfactant: Fluorad FC-170C; fluoroalkyl                               ester manufactured by Sumitomo 3M Ltd.)                                       Surfactant                3.0                                                 (hydrocarbon surfactant: Noigen EA-170: poly-                                 oxyethylene alcohol phenyl ether manufactured                                 by Dai-ichi Kogyo Seiyaku Co., Ltd.)                                          Ion-exchanged water       45.0                                                Total                     100                                                 ______________________________________                                    

The ink was prepared in a similar manner as that of Example 37. Thethermoplastic resin used herein had a particle diameter of about 0.3 μmand a softening point of 73° C.

Printing Test

The inks of the examples of the present invention and the comparativeexamples were tested in (1) the ink jet recording device of the presentinvention or (2) the conventional intermediate transfer ink jetrecording device (wherein an ink image is not heated on the transferdrum). The results are given below.

Evaluation items and criteria for the evaluation were as follows.

(1) Jetting stability

The nozzles were allowed to remain opened under an environment of 20° C.for a predetermined period of time. The jetting stability was thenevaluated based on whether or not the ink could be jetted through allthe nozzles.

Successful jetting of the ink through all the nozzles was observed afteropening of the nozzles for 5 min . . . ∘

Successful jetting of the ink through all the nozzles was observed afterallowing the nozzles to remain opened for 1 to less than 5 min . . . Δ

Successful jetting of the ink through all the nozzles was not observedafter allowing the nozzles to remain opened for 1 min . . . x

(2) Clogging after standing for long period of time

The nozzles were allowed to remain opened under an environment of 45° C.for a predetermined period of time. The clogging was then evaluatedbased on whether or not clogging occurred.

Clogging was not observed after allowing the nozzles to remain openedfor 10 days . . . ∘

Clogging was not observed after allowing the nozzles to remain openedfor 5 days but observed after allowing the nozzles to remain opened for10 days . . . Δ

Clogging was observed after allowing the nozzles to remain opened for 5days . . . x

(3) Print density

The print density in terms of average OD value was measured with amicrodensitometer (manufactured by Konica Corp.).

OD value of 1.4 or more . . . ∘

OD value of less than 1.4 to 1.2 or more . . . Δ

OD value of less than 1.2 . . . x

(4) Sharpness of edge

The state of the edge of the print was evaluated with the naked eye.

The edge was sharp independently of the print pattern . . . ∘

The edge was disturbed depending upon the print pattern . . . Δ

The whole edge was disturbed with blurred image . . . x

(5) Adaptability to paper

100 kinds in total of paper including copying paper, bond paper andregenerated paper were printed. The number of kinds of paper, whichprovided a print having an OD value of 1.4 or more and had a sharp edgeindependently of the print pattern was regarded as the percentageadaptability to paper of the ink composition.

Percentage adaptability to paper of 97% or more . . . ∘

Percentage adaptability to paper of less than 97% to 90% . . . Δ

Percentage adaptability to paper of less than 90% . . . x

(6) Rubbing resistance

The print was allowed to stand for 10 min after printing, and then thesurface of the print was rubbed with a finger. The rubbing resistance ofthe print was evaluated based on whether or not a stain occurred on theprint face.

No stain was observed even when the print was rubbed strongly . . . ∘

A stain distinguishable with the naked eye occurred when the print wasrubbed strongly . . . Δ

A stain distinguishable with the naked eye occurred even when the printwas rubbed weakly . . . x

(7) Water resistance

The water resistance was evaluated as follows. When the print wasbrought to contact with water,

the print was not blurred at all . . . ∘

the print at its edge was blurred . . . Δ

the print was washed away . . . x

(8) Quick drying property

The quick drying property was evaluated based on the time necessary forcausing no stain when a finger touched the print after printing.

Time necessary for causing no stain of the print was less than 15 sec .. . ∘

Time necessary for causing no stain of the print was sec to 1 min . . .Δ

A smudge occurred when a finger touched the print even 10 min afterprinting . . . x

(9) Storage stability

The storage stability was evaluated based on whether or not anagglomerate occurred when the ink composition was allowed to stand underan environment of 45° C.

No agglomerate occurred even when the ink composition was allowed tostand for one year . . . ∘

An agglomerate occurred when the ink composition was allowed to standfor 6 months to one year . . . Δ

An agglomerate occurred when the ink composition was allowed to standfor one month . . . x

(10) Image untransferred

The ink image was transferred to a recording medium at a transferpressure of 1.0 kg/cm. The weight of the ink on the transfer mediumbefore and after transfer of the ink image to the recording medium. Thepercentage of image untransferred was determined by the followingequation. ##EQU1##

Percentage of image untransferred of 0% . . . excellent (⊚)

Percentage of image untransferred of 0 to less than 2% . . . good (∘)

Percentage of image untransferred of 2% or more . . . poor (x)

(11) Dropout

The proportion of the number of missed dots relative to the number ofnecessary dots per unit area of the print was expressed in percentage.

0% . . . excellent (⊚)

0 to less than 2% . . . good (∘)

2% or more . . . poor (x)

(12) Unevenness of density

A solid print portion of the print was scanned with a microdensitometer(manufactured by Konia Corp.) to measure the difference between themaximum OD value and the minimum OD value.

Difference of 0.1 or less . . . excellent (⊚)

Difference of 0.1 to less than 0.2 . . . good (∘)

Difference of 0.2 or more . . . poor (x)

(13) State of peeling layer formed

The state of "peeling layer" formed between the transfer drum and theink image was observed.

The peeling layer was satisfactorily formed . . . ∘

The peeling layer was formed but unsatisfactory . . . Δ

The peeling layer was not formed . . . x

(14) Transfer of image from transfer medium to recording medium

The transfer pressure necessary for realizing a percentage transfer ofapproximately 100% was measured. The pressure was measured by means of"Tacking Tester LT-25A-500" (manufactured by Resuka K.K.).

The pressure was: 3 kg/cm² or less . . . ∘ more than 3.1 kg/cm² to 5kg/cm² or less . . . Δ 5.1 kg/cm² or more . . . x

(15) Transfer pressure and percentage of image untransferred

The relationship between the transfer pressure and the percentage ofimage untransferred was examined under various printing conditions. Thetime taken for the ink image to be transferred from the transfer drum tothe transfer medium was 10 sec at the printing initiation portion and 2sec at the printing termination portion. The print was evaluated asfollows.

Percentage of image untransferred of 0% with no change in image . . . ∘

Percentage of image untransferred of less than 5% with deformation ofimage . . . Δ

Percentage of image untransferred of 5% or more with occurrence ofdropout and deformation of image . . . x

The results were as given in the following tables.

                  TABLE 1                                                         ______________________________________                                                     Evaluation items                                                                    (10)              (12)                                             Recording  Image      (11)   Unevenness                               Ink     device     untransferred                                                                            Dropout                                                                              of density                               ______________________________________                                        Example 1                                                                             Device     ⊚                                                                         ⊚                                                                     ⊚                         Example 1                                                                             Conventional                                                                             ◯                                                                            X      X                                                device                                                                ______________________________________                                         *: The surface of the transfer medium had a temperature of 100° C.     for the device (1) and was not heated (25° C.) for the conventiona     device.                                                                  

                                      TABLE 2                                     __________________________________________________________________________                      Evaluation items                                                              (1)       (3) (4)  (5)    (6)  (7)  (8)                                       Jetting                                                                            (2)  Print                                                                             Edge Adaptability                                                                         Rubbing                                                                            Water                                                                              Quick                   Inks   Recording device                                                                         stability                                                                          Clogging                                                                           density                                                                           sharpness                                                                          to paper                                                                             resistance                                                                         resistance                                                                         drying                  __________________________________________________________________________    Example 2                                                                            Device (1) ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 3                                                                            "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 4                                                                            "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 5                                                                            "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 6                                                                            "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 7                                                                            "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 8                                                                            "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 9                                                                            "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 10                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 2                                                                            Conventional Device                                                                      ◯                                                                      ◯                                                                      Δ                                                                           X    X      X    Δ                                                                            X                       Example 3                                                                            "          ◯                                                                      ◯                                                                      Δ                                                                           X    X      X    Δ                                                                            X                       Example 4                                                                            "          ◯                                                                      ◯                                                                      Δ                                                                           X    X      X    X    X                       Example 5                                                                            "          ◯                                                                      ◯                                                                      X   X    X      X    Δ                                                                            X                       Example 6                                                                            "          ◯                                                                      ◯                                                                      X   X    X      X    X    X                       Example 7                                                                            "          ◯                                                                      ◯                                                                      ◯                                                                     X    Δ                                                                              Δ                                                                            X    Δ                 Example 8                                                                            "          ◯                                                                      ◯                                                                      ◯                                                                     X    Δ                                                                              Δ                                                                            X    Δ                 Example 9                                                                            "          ◯                                                                      ◯                                                                      Δ                                                                           X    X      X    Δ                                                                            X                       Example 10                                                                           "          ◯                                                                      ◯                                                                      X   X    X      X    Δ                                                                            X                       Comparative                                                                          Device (1) ◯                                                                      ◯                                                                      X   X    Δ                                                                              X    X    ◯           Example 2                                                                     Comparative                                                                          "          ◯                                                                      ◯                                                                      X   X    X      X    Δ                                                                            X                       Example 3                                                                     Comparative                                                                          "          Δ                                                                            X    Δ                                                                           Δ                                                                            Δ                                                                              ◯                                                                      ◯                                                                      ◯           Example 4                                                                     __________________________________________________________________________

                                      TABLE 3                                     __________________________________________________________________________                      Evaluation items                                                              (1)       (3) (4)  (5)    (6)  (7)  (8)                                       Jetting                                                                            (2)  Print                                                                             Edge Adaptability                                                                         Rubbing                                                                            Water                                                                              Quick                   Inks   Recording device                                                                         stability                                                                          Clogging                                                                           density                                                                           sharpness                                                                          to paper                                                                             resistance                                                                         resistance                                                                         drying                  __________________________________________________________________________    Example 11                                                                           Device (1) ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 12                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 13                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 14                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 15                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 16                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 17                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 11                                                                           Conventional Device                                                                      ◯                                                                      ◯                                                                      Δ                                                                           X    X      X    Δ                                                                            X                       Example 12                                                                           "          ◯                                                                      ◯                                                                      Δ                                                                           X    X      X    Δ                                                                            X                       Example 13                                                                           "          ◯                                                                      ◯                                                                      Δ                                                                           X    X      X    X    X                       Example 14                                                                           "          ◯                                                                      ◯                                                                      X   X    X      X    Δ                                                                            X                       Example 15                                                                           "          ◯                                                                      ◯                                                                      X   X    X      X    X    X                       Example 16                                                                           "          ◯                                                                      ◯                                                                      Δ                                                                           X    X      X    Δ˜.largecircl                                                     e.   X                       Example 17                                                                           "          ◯                                                                      ◯                                                                      Δ                                                                           X    X      X    Δ˜.largecircl                                                     e.   X                       Comparative                                                                          Device (1) ◯                                                                      ◯                                                                      Δ                                                                           Δ                                                                            Δ                                                                              X    Δ                                                                            X                       Example 5                                                                     Comparative                                                                          "          Δ                                                                            X    Δ                                                                           Δ                                                                            X      X    Δ                                                                            ◯           Example 6                                                                     Comparative                                                                          "          Δ                                                                            X    Δ                                                                           Δ                                                                            Δ                                                                              ◯                                                                      ◯                                                                      ◯           Example 7                                                                     Comparative                                                                          "          X    Δ˜X                                                                    ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 8                                                                     __________________________________________________________________________

                                      TABLE 4                                     __________________________________________________________________________                            Surface temperature of transfer medium                                        (°C.)                                          Inks   Recording device                                                                       Evaluation item                                                                       50 70  90                                                                              140                                                                              160 180                                   __________________________________________________________________________    Example 18                                                                           Device (1)                                                                             (10)    X  ⊚                                                                  ⊚                                                                ⊚                                                                 ⊚                                                                  X                                            "        (13)    X  ◯                                                                     ◯                                                                   ◯                                                                    ◯                                                                     X                                            "        (14)    X  ◯                                                                     ◯                                                                   ◯                                                                    ◯                                                                     X                                     Example 19                                                                           "        (10)    X  ⊚˜◯                                              ⊚                                                                ⊚                                                                 ⊚˜◯                                              X                                            "        (13)    X  ◯˜Δ                                                       ◯                                                                   ◯                                                                    ◯                                                                     X                                            "        (14)    X  ◯                                                                     ◯                                                                   ◯                                                                    ◯                                                                     X                                     Example 20                                                                           "        (10)    X  X   ⊚                                                                ⊚                                                                 ⊚                                                                  X                                            "        (13)    X  ◯˜Δ                                                       ◯                                                                   ◯                                                                    ◯                                                                     X                                            "        (14)    X  ◯                                                                     ◯                                                                   ◯                                                                    ◯                                                                     X                                     Comparative                                                                          "        (10)    X  X   X X  X   X                                     Example 9                                                                            "        (13)    X  X   X X  X   X                                            "        (14)    X  X   X X  X   X                                     __________________________________________________________________________

                                      TABLE 5                                     __________________________________________________________________________                      Evaluation items                                                              (1)       (3) (4)  (5)    (6)  (7)  (8)                                       Jetting                                                                            (2)  Print                                                                             Edge Adaptability                                                                         Rubbing                                                                            Water                                                                              Quick                   Inks   Recording device                                                                         stability                                                                          Clogging                                                                           density                                                                           sharpness                                                                          to paper                                                                             resistance                                                                         resistance                                                                         drying                  __________________________________________________________________________    Example 21                                                                           Device (1) ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯˜Δ                                                          ◯                                                                      ◯                                                                      ◯           Example 22                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯˜Δ                                                          ◯                                                                      ◯                                                                      ◯           Example 23                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯˜Δ                                                          ◯                                                                      ◯                                                                      ◯           Example 24                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯˜Δ                                                          ◯                                                                      ◯                                                                      ◯           Example 25                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯˜Δ                                                          ◯                                                                      ◯                                                                      ◯           Example 26                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯˜Δ                                                          ◯                                                                      ◯                                                                      ◯           Example 21                                                                           Device (2) ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 22                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 23                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 24                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 25                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 26                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 21                                                                           Conventional Device                                                                      ◯                                                                      ◯                                                                      X   X    X      X    X    Δ                 Example 22                                                                           "          ◯                                                                      ◯                                                                      Δ                                                                           X    X      X    X    X                       Example 23                                                                           "          ◯                                                                      ◯                                                                      Δ                                                                           X    X      X    X    Δ                 Example 24                                                                           "          ◯                                                                      ◯                                                                      X   X    X      X    X    X                       Example 25                                                                           "          ◯                                                                      ◯                                                                      X   X    X      X    X    Δ                 Example 26                                                                           "          ◯                                                                      ◯                                                                      X   X    X      Δ                                                                            X    Δ                 Comparative                                                                          Device (2) ◯                                                                      ◯                                                                      X   X    Δ                                                                              X    X    ◯           Example 10                                                                    Comparative                                                                          "          X    X    Δ                                                                           X    X      ◯                                                                      ◯                                                                      ◯           Example 11                                                                    Comparative                                                                          "          X    X    ◯                                                                     ◯                                                                      ◯                                                                        Δ                                                                            ◯                                                                      X                       Example 12                                                                    Comparative                                                                          "          ◯                                                                      ◯                                                                      Δ                                                                           Δ                                                                            Δ                                                                              X    X    ◯           Example 13                                                                    __________________________________________________________________________

                                      TABLE 6                                     __________________________________________________________________________                      Evaluation items                                                              (1)       (3) (4)  (5)    (6)  (7)  (8)                                       Jetting                                                                            (2)  Print                                                                             Edge Adaptability                                                                         Rubbing                                                                            Water                                                                              Quick                   Inks   Recording device                                                                         stability                                                                          Clogging                                                                           density                                                                           sharpness                                                                          to paper                                                                             resistance                                                                         resistance                                                                         drying                  __________________________________________________________________________    Example 27                                                                           Device (2) ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 28                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 29                                                                           "          Δ                                                                            Δ                                                                            ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 30                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯           Example 27                                                                           Conventional Device                                                                      ◯                                                                      ◯                                                                      Δ                                                                           Δ                                                                            ◯                                                                        X    Δ                                                                            X                       Example 28                                                                           "          ◯                                                                      ◯                                                                      Δ                                                                           Δ                                                                            ◯                                                                        X    Δ                                                                            X                       Example 29                                                                           "          Δ                                                                            Δ                                                                            Δ                                                                           Δ                                                                            ◯                                                                        Δ                                                                            ◯                                                                      Δ                 Example 30                                                                           "          ◯                                                                      ◯                                                                      Δ                                                                           Δ                                                                            ◯                                                                        X    X    X                       Comparative                                                                          Device (2) ◯                                                                      Δ                                                                            Δ                                                                           X    Δ                                                                              X    X    Δ                 Example 14                                                                    Comparative                                                                          "          X    X    X   X    Δ                                                                              Δ                                                                            Δ                                                                            ◯           Example 15                                                                    __________________________________________________________________________

                                      TABLE 7                                     __________________________________________________________________________                      Evaluation items                                                              (1)       (3) (4)  (5)    (6)  (7)  (8) (9)                                   Jetting                                                                            (2)  Print                                                                             Edge Adaptability                                                                         Rubbing                                                                            Water                                                                              Quick                                                                             Storage             Inks   Recording device                                                                         stability                                                                          Clogging                                                                           density                                                                           sharpness                                                                          to paper                                                                             resistance                                                                         resistance                                                                         drying                                                                            stability           __________________________________________________________________________    Example 31                                                                           Device (2) ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯                                                                     ◯       Example 32                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯                                                                     ◯       Example 33                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯                                                                     ◯       Example 34                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯                                                                     ◯       Example 35                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯                                                                     ◯       Example 36                                                                           "          ◯                                                                      ◯                                                                      ◯                                                                     ◯                                                                      ◯                                                                        ◯                                                                      ◯                                                                      ◯                                                                     ◯       Example 31                                                                           Conventional Device                                                                      ◯                                                                      ◯                                                                      Δ                                                                           Δ                                                                            ◯                                                                        X    X    X   ◯       Example 32                                                                           "          ◯                                                                      ◯                                                                      Δ                                                                           Δ                                                                            ◯                                                                        X    X    X   ◯       Example 33                                                                           "          ◯                                                                      ◯                                                                      Δ                                                                           Δ                                                                            ◯                                                                        X    X    X   ◯       Example 34                                                                           "          ◯                                                                      ◯                                                                      Δ                                                                           Δ                                                                            ◯                                                                        X    X    X   ◯       Example 35                                                                           "          ◯                                                                      ◯                                                                      Δ                                                                           Δ                                                                            ◯                                                                        X    X    X   ◯       Example 36                                                                           "          ◯                                                                      ◯                                                                      Δ                                                                           Δ                                                                            ◯                                                                        X    X    X   ◯       Comparative                                                                          Device (2) ◯                                                                      ◯                                                                      X   X    Δ                                                                              X    X    ◯                                                                     ◯       Example 16                                                                    Comparative                                                                          "          ◯                                                                      ◯                                                                      X   X    X      ◯                                                                      ◯                                                                      ◯                                                                     ◯       Example 17                                                                    Comparative                                                                          "          X    X    ◯                                                                     ◯                                                                      ◯                                                                        Δ                                                                            ◯                                                                      ◯                                                                     X                   Example 18                                                                    Comparative                                                                          "          ◯                                                                      ◯                                                                      Δ                                                                           Δ                                                                            ◯                                                                        X    X    ◯                                                                     ◯       Example 19                                                                    __________________________________________________________________________

                                      TABLE 8                                     __________________________________________________________________________                  Evaluation items                                                              (16) Transfer efficiency                                        Ink and       0.6 kg/cm    1.0 kg/cm    1.5 kg/cm                             recording process                                                                           100% duty                                                                           Line   100% duty                                                                           Line   100% duty                                                                           Line   (6)  (7)                       Recording                                                                             printing                                                                            printing                                                                             printing                                                                            printing                                                                             printing                                                                            printing                                                                             Rubbing                                                                            Water               Ink   device  after 2 sec.                                                                        after 10 sec.                                                                        after 2 sec.                                                                        after 10 sec.                                                                        after 2 sec.                                                                        after 10 sec.                                                                        resistance                                                                         resistance          __________________________________________________________________________    Example 37                                                                          Device (1)                                                                            ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        ◯                                                                      ◯       Example 38                                                                          "       ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        ◯                                                                      ◯       Example 39                                                                          "       ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        ◯                                                                      ◯       Example 37                                                                          Device (2)                                                                            ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        ◯                                                                      ◯       Example 38                                                                          "       ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        ◯                                                                      ◯       Example 39                                                                          "       ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        ◯                                                                      ◯       Example 37                                                                          Conventional                                                                          ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        ◯                                                                       ◯                                                                        X    X                         device                                                                  __________________________________________________________________________

We claim:
 1. An intermediate transfer ink jet recording methodcomprising the steps of:ejecting an ink composition comprising water, athermoplastic resin, a colorant and a water-soluble organic solvent onan intermediate transfer medium to form an ink image having a firstshape; heating said ink image to a heated state at or above thesoftening or melting temperature of said thermoplastic resin so as tobring the ink image on the intermediate transfer medium into the form ofa film having a surface that is viscous, whereby the ink image in theheated state has a second shape, said second shape having a thickness of2-10 microns; and interfacially transferring said ink image in theheated state on said transfer medium to a recording medium so assubstantially to maintain said second shape.
 2. The ink jet recordingmethod according to claim 1, wherein the softening or meltingtemperature of the thermoplastic resin contained in the ink compositionis in the range of from 50° to 150° C.
 3. The ink jet recording methodaccording to claim 1, wherein said thermoplastic resin contained in theink composition is a water-insoluble resin.
 4. The ink jet recordingmethod according to claim 3, wherein said water-insoluble resincontained in said ink composition is in the form of a resin emulsion. 5.The ink jet recording method according to claim 1, wherein saidthermoplastic resin contained in said ink composition is a water-solubleresin.
 6. The ink jet recording method according to claim 1, whereinsaid thermoplastic resin and said colorant contained in said inkcomposition are integrated with each other to form colored resinparticles.
 7. The ink jet recording method according to claim 1, whereinsaid ink composition further comprises a surfactant.
 8. The ink jetrecording method according to claim 1, wherein said ink compositionfurther comprises a water-soluble polymer.
 9. The ink jet recordingmethod according to claim 1, wherein said ink composition furthercomprises a saccharide.
 10. The ink jet recording method according toclaim 1, wherein said temperature of at least the softening or meltingtemperature of said thermoplastic resin is in the range of from 50° to200° C.
 11. An intermediate transfer ink jet recording method comprisingthe steps of:ejecting an ink composition comprising water, athermoplastic resin, a colorant and a water-soluble organic solvent and,when said thermoplastic resin is a water-insoluble resin, furthercomprising a water-soluble polymer on an intermediate transfer medium toform an ink image having a first shape; concentrating said ink image byheating to a heated state in a first heating so as to bring the inkimage on the intermediate transfer medium into the form of a film havinga surface that is viscous, whereby the ink image in the heated state hasa second shape said second shape having a thickness of 2-10 microns;interfacially transferring said ink image in the heated state on saidtransfer medium to a recording medium so as substantially to maintainsaid second shape; and heating said ink image in a second heating onsaid recording medium to at least the softening or melting temperatureof said thermoplastic resin.
 12. The ink jet recording method accordingto claim 11, wherein the softening or melting temperature of thethermoplastic resin contained in the ink composition is in the range offrom 50° to 150° C.
 13. The ink jet recording method according to claim11, wherein said thermoplastic resin contained in the ink composition isa water-insoluble resin.
 14. The ink jet recording method according toclaim 13, wherein said water-insoluble resin contained in said inkcomposition is in the form of a resin emulsion.
 15. The ink jetrecording method according to claim 11, wherein said thermoplastic resincontained in said ink composition is a water-soluble resin.
 16. The inkjet recording method according to claim 11, wherein said thermoplasticresin and said colorant contained in said ink composition are integratedwith each other to form colored resin particles.
 17. The ink jetrecording method according to claim 11, wherein said ink compositionfurther comprises a surfactant.
 18. The ink jet recording methodaccording to claim 11, wherein said ink composition further comprises awater-soluble polymer.
 19. The ink jet recording method according toclaim 11, wherein said ink composition further comprises a saccharide.20. The ink jet recording method according to claim 11, wherein saidtemperature of at least the softening or melting temperature of saidthermoplastic resin is in the range of from 50° to 200° C.